This is a Hi-Viz Sight known as the Interchangeable, model SWMPE21.
HIVIZ(R) Interchangeable Front & Rear Sight Set for Smith & Wesson M&P pistols. Fits full size and Pro models in 9mm" 40 S&W & .45 ACP; does not fit CORE models. Front sight includes Green" Red and White replaceable LitePipes. Rear sight includes Green" Red and Black replaceable LitePipes.
Features:
Adjustable sight set
Front includes green red and white replaceable LitePipes;Rear includes green red and black replaceable LitePipes
Front Litepipe diameter .090
Rear Litepipe diameter .078
