Intended for use on the SHIELD PLUS frames. (these typically have 10 & 13 round magazines)This unit fits in the bottom rear cavity of the M&P Shield PLUS utilizing a friction fit to secure it in the frame. This insert is designed to keep out dust and debris as well as finish off the overall look of the frame.*** NOT FOR 45 ACP MODELS/EQUALIZER/EZ FRAMES/ORIGINAL SHIELD FRAMES