INCLUDED IN THIS KIT. REMINGTON 870 MAG TUBE COUPLING – MATTE BLACK – F99833. REMINGTON 870 MAGAZINE TUBE EXTENTION ASSEMBLY (2 – SHOT) – F29768. REMINGTON 870 MAGAZINE EXTENTION SLEEVE BLACK COMPLETE – F407860. REMINGTON 870 MAGAZINE SPRING 7-SHOT – F94645. REMINGTON 1187 MAGAZINE EXTENTINO SWIVEL ASSEMBLY PARKERIZED – F103259.