Sled Legs are wearable mini sleds that you can attach to the bottom half of your legs and allow you to slide down a hill on just your knees. Currently in a funding phase on IndieGoGo at a price point of $84 for a pair, which is said to be a 40% discount off of the future retail price of $139.95. The sleds attach to your legs using 2 straps, one around your knees, the other around your ankles, and come in two different sizes to accommodate both taller and shorter people.
Sled Legs are made with foam attached to the inside of the sleds to pad your legs and knees when you smash down upon them. I'm going to go ahead and guess these aren't made for anyone over 28ish, as if I were to use them I would surely pop a knee open after the 2nd or 3rd attempt.
The outer shell of the Sled Legs are made up of ABS plastic, and each sled has 4 ridges on it that help guide the sleds down the hill in a straight line.