The Midwest Industries Alpha Folding Stock is compatible with firearms that include 1913 rail adaptor. Shipped for rifle use, the assembly is also compatible with the Gear Head Works tailhook for arm brace use (sold separately). The reversible design makes the Alpha stock comfortable for left-handed shooters and can be configured to right or left folding. FeaturesAdjustable polymer cheek piece for comfortable use with all usersAdjustable butt pad for increased usability with plate carriers or heavy gear5 position locking beam with textured button for quick changingHeavy-duty side-folding mechanism constructed from 4140 heat treated steelFull-length locking lug for maximum strengthSolid positive lock up in both positionsSteel clamp with large surface engagementFeatures 3 QD sling attachmentsCurved, adjustable top surface for a comfortable cheek weldAdds 0.75" to the length of the firearm in the folded positionConstructed of high strength polymer, aluminum, and steel components