The Brownell's number is 940-000-983. This is for the assembly with a mag disconnect but no internal lock. This will reduce your trigger pull a little bit because it uses the lighter sear spring. You'd still need to change out your trigger bar and trigger spring to achieve the standard M&P pull (around 6.5 pounds). There are people over on the mp-pistol.com forum who have been waiting over 8 weeks for one to show up in stock. They've been on backorder forever. I've been trying to get one. They are near impossible to get.