The multi position stock. Locks in a single slot instead of two. In previous models the lock had to engage in 2 positions. Seemed like a great idea, double locks. Unfortunately our customers thought they could lock there rifles stock in 2 positons but it was only one. If only one lock was in the stock could collapse and smash you. So we got rid of that, the stock locks in any groove now about every inch, and is truly positive. All new M96 Windrunners come with it. It's a great upgrade and requires the whole rifle to be shipped in. Were always making improvements.