REFILL: iON SYNC® DIY Earthing Shoe Plugs
REFILL: iON SYNC® DIY Earthing Shoe Plugs
REFILL: iON SYNC® DIY Earthing Shoe Plugs
REFILL: iON SYNC® DIY Earthing Shoe Plugs
REFILL: iON SYNC® DIY Earthing Shoe Plugs
REFILL: iON SYNC® DIY Earthing Shoe Plugs

REFILL: iON SYNC® DIY Earthing Shoe Plugs

Earth Runners Sandals - Reconnecting Feet with Nature
$26

Our innovative iON SYNC® Earthing Plugs have been developed over several years of dedicated research and development to create a highly durable and conductive solution for enthusiasts of earthing shoes.

When installed through the soles of shoes, iON SYNC® plugs offer users an unparalleled grounding experience that replicates the benefits of being barefoot.

These plugs are offered in three sizes, suitable for grounding shoes with thicknesses ranging from 4-15mm (3/16 - 5/8"). Please refer to this table to find the right size for your shoes, and find written -and- video instructions below.

Skive: If your shoes don't have an adequate recession in the outsole tread pattern profile for the barb of the plug to sit, you can use our skiving tool (Sold separately) to remove any needed lugs from the outsole to create a recession in your shoe’s tread for the barb to sit. View our video below to learn how to use the Skive.

Base Sole Thickness = Stack height - Lug he 
Looking for the full Kit with tools? Check out our iON SYNC® DIY Earthing Shoe Kit!


FAQ

What if I can't decide where to put the plug?

If you need help figuring out where to put the iON SYNC earthing plug in your shoes and what size to choose, contact one of our earthing support experts and send a picture of the bottom of your shoes.

Can the iON SYNC® earthing plug be removed?

Yes, you can push the earthing plug through from the bottom by pressing hard with a medium sized philips screw driver (or something similar in diameter) on the flat barb surface after the pull tab has been removed.

Can the iON SYNC® earthing plug be removed and reinstalled?

No, our earthing plugs can only be installed once. Once they are installed they can’t be reinstalled.

Are iON SYNC® earthing plug watertight?

Yes, the compression fit rubber design up our earthing plugs mates with shoe outsole making a watertight seal when installed properly.

What makes these rubber iON SYNC® earthing plugs conductive?

We worked with industry leading polymer experts to formulate a proprietary rubber formulation featuring a conductive filler to create a conductive network throughout the material that allows for electron transfer of low voltages--great for earthing.

How do I determine what size earthing plug to use for my shoes?

Determine the base thickness of your shoes (Base thickness = Stack height - Lug height) and then refer to our sizing chart. Most shoe manufacturers list the stack height (total sole thickness) on their product page. Then you just need to measure and subtract the lug height to account for the recession where you plan to install the earthing plug in the middle of the outsole. The height of lugs usually range from 2-5mm based on their level of all terrain grip.

If the base thickness of my sole is on the cusp of two different iON SYNC® earthing plug sizes, should I order big or small?

We recommend going with the bigger size iON SYNC® earthing plug if the base thickness of your sole is on the threshold of two sizes.

Do you feel the iON SYNC® earthing plug underfoot?

If you properly install the earthing plug in the middle of the sole with the right size recessed into the outsole, you should feel it slightly when wearing your grounded shoes for the first time. After ~1 hour the sensation will normalize and you will forget it's there.

Do the iON SYNC® earthing plugs work with socks?

Due to the weight of your body bearing down onto the head of the earthing plug head, combined with the common perspiration of our sole into socks, our testing has shown a negligible difference in the measurable voltage drop between when earthing wearing ion sync grounded shoes with and without socks.

Can you remove the iON SYNC® earthing plug once it's been installed?

Our iON SYNC® plugs are designed for one-time use; they can only be installed once. If your earthing plug becomes compromised due to reasons such as accidentally cutting the barb too small, the barb becoming worn out, the plug falling out, or accidentally installing the wrong size plug, you can remove them using a Philips screwdriver from the outsole side.

Is the iON SYNC® earthing plug through the sole watertight?

Yes, our earthing plugs have been tested to be watertight across various shoes in our testing. The barb of our iON SYNC® plugs features a suction cup design to create a watertight seal with the outsole when properly installed. Here are some tips to ensure a watertight seal:

Use the recommended plug size based on the thickness of your sole, ensuring to subtract the thickness of the lugs to account for the thickness of the base sole. This ensures the elasticity of the polymer plug creates a compression seal with the outsole.

Use the correct hole punch size for your plug size to ensure the plug can freely compress and achieve a proper watertight seal.

Ensure the outsole area around the hole is large and flat enough for the barb to mate with and achieve an uninterrupted watertight compression fit.

Ensure the barb is well protected via a void in the middle of the outsole that is at least 1.5-2mm deep to protect it from abrasion, blunt force, and excessive wear.

What makes the polymer earthing plugs conductive?

Recent advancements in conductive polymer research, particularly in high-performance molecular materials, have led to exciting design possibilities, including our new iON SYNC® earthing technology. Through persistent effort and global networking, we collaborated with a leading compounding company experienced in working with industry giants like Apple, Tesla, and SpaceX. After more than 15 iterations, we formulated a compound that combines the durability of shoe outsole rubber with the required conductivity, meeting the standards for therapeutic earthing (less than 10^3 Ohms resistance). Our conductive lattice-infused polymer has been precisely designed to strike a balance of mechanical and electrical properties to achieve our easy-to-install earthing plug application.

How do I decide what size earthing plug to use?

The right size plug for your shoe is determined by the stack height minus the lug height, which equals the base height. If you are uncertain about what size to use, please feel free to ask our Customer Service team for assistance.

Do the iON SYNC® earthing plugs work with socks?

Due to the weight of your body bearing down onto the head of the earthing plug head, combined with the common perspiration of our sole into socks, our testing has shown a negligible difference in the measurable voltage drop between when earthing wearing ion sync grounded shoes with and without socks.

How does the material and construction of different socks affect one’s earthing potential in iON SYNC® grounded footwear?

The two factors to consider regarding the conductivity of socks in earthing shoes is their weight and wicking potential of the fiber composition. The heavier the weight of the sock results in more distance between the foot and the plug and the more wicking volume and therefore more time/sweat to saturate the sock with perspiration to make the sock conductive.

The other factor to consider is the wicking ability of the fibers used in the sock. Natural fibers have great wicking properties while only some synthetic fibers do. Polyester COOLmax fibers for example, or other similar engineered fibers that feature a capillary filament profile, have good wicking capabilities that give rise to conductive properties via perspiration.

Do the iON SYNC® earthing plugs release microplastics?

Our earthing plugs use a polymer that is food-safe. Food-safe polymers do not release microplastics into food or the environment.

How do socks affect grounding?

The conductivity of socks in earthing shoes depends on their weight and the wicking ability of the material. Heavier socks create more distance between your foot and the plug, while also holding more sweat before becoming saturated. The type of fiber in the sock also affects wicking. Natural fibers and some synthetics like Polyester COOLmax have good wicking properties due to their capillary structure.

How does the iON SYNC® rubber earthing plug kit compare to the Shoe Syce copper earthing rivet kit?

Comfort:  iON SYNC® [more comfortable than]  Shoe Sync copper

Installation difficulty:  iON SYNC® rubber [easier to install than] Shoe Sync copper

Conductivity:  iON SYNC® rubber [less conductive than] Shoe Sync copper

Does wearing iON SYNC® grounded plugs increase your chances of absorbing excessive ground current via a peripheral lightening strike?

Wearing iON SYNC® grounded footwear provides a similar experience to being barefoot during a storm. However, the conductance of iON SYNC® plugs is designed to handle limited low amperage and voltage, which prevents the transfer of harmful amounts of ground current from a lightning strike through the plug and into your foot. It is important to note that the limited low amperage and voltage capabilities of iON SYNC® plugs do not have a negative impact on the low amperage and voltage range within which earthing operates.  

How does the installation of the plug affect the water-proofing of the sole? Have you tested the water seal? 

Our iON SYNC® earthing plugs are designed with a barb that connects with the outsole of the shoe, having a plunger-like shape to enhance the seal, much like an o-ring commonly used in plumbing. The polymer hardness of our iON SYNC® plugs is designed to conform to the shoe profile, ensuring a secure seal. Through extensive testing, we have determined that when the right plug size is correctly installed in the suitable shoe sole thickness, achieving the proper compression fit, we have successfully prevented water from seeping through the sole.

What if it’s really hard to pull the earthing plug barb through the hole and seat it on the outsole?

Solution 1: Use something like a screwdriver or a pen to pre stretch the hole through the center of your shoe before rehoming and quickly installing the earthing plug.

Solution 2: Use the next size up earthing plug that is a bit longer.

Solution 3: Use the next size up hole punch to cut a slightly bigger hole. (This should be your last resort.)

Specs

Our collaboration with a renowned compounding company, known for its work with top technology firms such as Apple, Tesla, and SpaceX, has resulted in the development of a unique composite material. This material blends the robust properties of shoe outsole rubber with the required conductivity to meet the standards for therapeutic earthing (less than 10^3 Ohms resistance).

Shipping

Your order will ship out via USPS within 3-7 business days of receiving it. All orders placed by Monday 7am Pacific will be shipped Thursday. Orders placed by Thursday at 7am Pacific will ship Monday. Any changes to your order must be requested within 24 hours of placing your order.

All sandals are made to order in our Sonoma County workshop. *Please note we cannot guarantee changes made to your order 24 hours after it has been placed*

Domestic:

  • First Class Mail cost $3-5 and takes 3-5 days for delivery from ship date.
  • Priority Mail (flat rate) cost ~$7 and takes 2-3 days for delivery from ship date.
  • Priority Mail Express (flat rate) cost $22.38 and takes 1-2 days for delivery from ship date.

International:

  • We ship worldwide with Delivered Duty Paid (DDP) shipping options to help avoid unpredictable customs fees and shipping delays. Shipped via FedEx, DHL & postal mail, taxes & duties included. Learn more here.

    • DDP Priority: average 9-14 day transit time.
    • DDP Express: average 7-10 day transit time.
    • DDP ePacket (Canada only): average 9-12 day transit time.

*shipping costs are estimated based on the weight of 1-3 items

1% Donation

1% donation for Tarahumara Indians

Earth Runners are inspired by ancient huarache running sandals. We are grateful to the Tarahumara for originating this design and feel fortunate to have the ability to give back and honor the creators of the huarache running sandal.

We donate 1% of all sales to True Messages, a non-profit focused on honoring the running heritage that remains so important to the Rarámuri culture. True Messages listens to the input of the local National community to determine where to allocate resources which includes sponsoring races, trail projects, and initiatives to support the youth of the community.

Thank you for helping us support the Tarahumara!