I ordered sights for a regular M&P 9, didn't know the CORE was different (Duh!). Customer Service went above and beyond (see my other review). I'm setting up M&P Pro 9 up for competition, and don't need co-witness. I installed this with a 1.0 Fiber Optic front sight and couldn't be happier. The wide 1.45 notch gives a great sight picture... Blackout rear and Fiber Optic front is the hot setup for competition.