I was at a sticking point in my attempts to to perform the full side splits, and just needed something to push my legs that bit further. I use this to perform leg-swings, and the first time I tried it, I managed to do the full-splits! Yep, not many people in the world can perform them.
I don't know how long it will last, but for the price I paid, it's already paid for itself several time over. Great stuff!