Base Material Properties


Though EvenKeel Performance Insoles are a relatively new product, we’ve been making custom orthotics based on the same patented model for years in our Brookline, MA office. In that time we have curated a list of materials that have excellent properties for various uses. For our custom insole, we simplified our use cases to keep the selection process easy for our customers without much experience in biomechanics and orthotic device composition. And we wanted to offer only products we know would outlast all others given that once they left our doors, they would not be coming back through.These materials would need to stand the test of time.

Layering materials is something we have done for years: place a soft layer atop a firm layer to achieve a supportive but comfortable device. Materials such as ethyl vinyl acetate (EVA), polyurethane foams (like Poron) and nitrogen blown polyethene (Plastizote) make up the bulk of the custom orthotics material we utilize.


nora® Lunatec combi is an innovative product development in composite sheets: two different materials are vulcanized together already during the manufacturing process and guarantee secure strength, without any bonding.


EvenKeel Soft Material:

NORA Vulcanized EVA - Lunatec Combi 2

The Combination of dual density EVA used in our Soft material base offering is formed as a single piece of foam in the manufacturing process. In a gist, two layers of liquid EVA are poured on one another and allowed to settle then nitrogen is added and the liquid becomes a flash hardened foam formed into a single material with two densities and durometers (hardness). To top layer (tan) is soft with a density of 22 Shore A (like touching a foam bath letter or a foam stress ball). The gray material around the heel area is a harder (30 shore A) with a greater density.

When we first encountered the German made vulcanized EVA in 2011 we were very impressed with the material’s ability to retain its integrity, never peel apart and deliver two varying densities in a seem-less bond. This means it will never peel apart for the duration of its life.

EvenKeel Firm Material

NORA Vulcanized EVA - Lunatec Combi 6

The Firm Combi 6 is also vulcanized EVA with layers that can not be separated without using a blade to do so. The top layer (orange) of this material is the same material as the gray bottom material on the Combi 2 above. It lies on top of the very firm layer of Shore 52 black EVA. This combination results in a significantly harder feel. Yet these are still sythetic rubber materials which gives them the ability to bend and flex as needed. Nevertheless - many people standing on a pair of firm EvenKeel Perfomance Insoles will find them as hard as a hard shell 3/4 length arch support.