BASTION Magazine Base Plate, Butt Plate for Smith & Wesson S&W M&P 9MM .40CAL SQH - VERITAS AEQUITAS Compatible with Smith & Wesson MP 9mm .40cal ONLY Fits both round and square hole base plate models Hard coat anodized black T6 machined aluminum Lasered artwork won't rub off; not painted Replaces factory plastic part