The Mesa Tactical Remington 870 Stock Adapter is a precision-engineered cast steel adapter that enables 12-gauge stocks to be used on 20-gauge Remington 870 shotguns significantly expanding your customization options.Mesa Tactical Remington 870 12Ga to 20Ga Stock AdapterCast steel construction for durability and reliabilityCompatible with Remington 870 20-gauge shotgunsAllows use of any 12-gauge Remington 870 stockOpens access to Mesa Tactical's Urbino Stocks telescoping adapters and Hydraulic Buffer systemsPerfect for 20-gauge Remington 870 owners who want to take advantage of the wider variety of 12-gauge stock options available including tactical and adjustable configurations.