Mudders "ARE" made from Resiprene-C! they are just made different.

Here is the description we got for the SS4:

"The Street Scrapper 4 marries the horsepower of Busse Combat's legendary INFI steel with the graceful ergonomics and comfort of our Resiprene C "Mudder" handles. The generous choil in front of the guard allows for the necessary choke-up when doing fine work and ease of sharpening the entire edge without bumping into the corner of the primary bevel plunge line. The INFI Street Scrapper 4 offers a formidable blade size for both carry along the trail or urban duty"

Specs at a glance:

Steel: INFI

Hardness: 58 - 60 Rc

Handle: Resiprene C

Thickness: 3/16"

Blade Length: 4"

Overall Length: 9"

When I first saw Mudders I was like "weird" and wondered about their feel and comfort.
After reading how nice they are and getting my big paws on them, I very quickly
found out how excellent they are, for a solid, comfortable grip, plus
being made from ResC I know they will last and take a beating!

They are my favorite handles for use and comfort ever! SY and Busse did it right
big time.