The Black Aces Tactical Mossberg Brace System is a 100% bolt on brace solution for the Mossberg 500 Series shotguns and Shockwaves. This system allows for better stability while firing. This system will fit the 500. 590, A1, Maverick 88, and even the ultra popular Shockwave. This system requires no modification to your system. FEATURES: ATI T3 Grip ATI 6 position tube with positive pin engagement to eliminate any chance of slippage while firing SB Tactical SBA3 Brace Drop SpacerAvailable in both Black and FDE (Grip & tube are black - color option is for brace only)