Presma Skeletonized Aluminum Pistol Arm Fin Black. 2 piece kit includes the brace and fin. Fits 1.25in tubes. 2 screw clamp system to hold to tube securely. Includes 2 M-LOK slots and 2 QR release holes Specifications for Presma Skeletonized Aluminum Pistol Arm Fin: Manufacturer: Presma Color: Black Gun Type: Rifle Length: 6 in Weight: 4.6 oz Diameter Compatibility: 1.25 in Stock/Brace Material: 7075 T6 Aluminum Condition: New Inner Diameter: 1.25 in Package Contents: Presma Skeletonized Aluminum Pistol Arm Fin Presma AAST17: Skeletonized Aluminum Pistol Arm Fin Black