The strip of leather that runs up and down the back of the inside of the boot lining to stiffen and support the boot top. Your heel “slides” down this piece when you’re putting on your boot. Also, called a “back stay” by some bootmakers.
Heel slides are in almost every pair of cowboy boots they are seldom as fancy as this pair. Heel slides are particularly important in a boot’s construction when a boot top is made out of a thinner leather, like kangaroo or kidskin. With everyday wear, boot tops made of thin or soft leather are likely to wrinkle and maybe even bunch at the ankles… if the top stitching and the heel slides weren’t providing support.
Pascal Davayat stitches each heel slide in the shape of an iron cross. His boots are about non-comformity inside and out.
(You can see more of Pascal’s work on the Hollywood Riff Raff instagram.)