GrovTec US Inc Shotgun Mag Cap with 1in Push Button Steel Swivel - Remington 870 Express/12 Gauge - Standard mag cap replaces factory cap and allows the use of any GrovTec push button swivel or even the multi-adaptor for speed and versatility in the field. Each set includes one 12 gauge mag cap and one standard 1in loop push button swivel. Replacement for Remington 870 Express/12 Gauge Black-oxide finish 1in swivel loop size