This device came as part of my CORE training introduced by Brandon and I liked it enough to buy one for $79.95 (all-in it's $99.65 when you add in taxes and shipping). Basically, it's a device that allows you to put a weight on it and use it to stretch your leg. Great design, use on a variety of leg exercises and the user gets to control the weight, brilliant!
Here's a brief website of it:
Here's a brief video of it: