Scorpion EVO 3 S1 pistol arm brace kit enables the addition of an aftermarket arm brace or other pistol buffer tube accessory adapter is made of 6061 t6 aluminum, flat black anodized buffer tube made by kak industries specifically for fitment of an aftermarket arm brace threads on adapter (1-3/16x16) are standard to accept all ar-15 buffer tubes/receiver extensions

if using a buffer tube other than the supplied kak industries tube there are two threaded alignment holes (10x32 thread) for tubes that use a notch for indexing. a 3/16 or 1/4 half dog socket set screw would be used for proper indexing. 

gunsmith installation is recommended

the sole intended use of the cz scorpion evo 3 s1 pistol arm brace adapter is to allow the attachment of an arm brace or other similar product to the pistol so that it may be fired in a manner consistent with all applicable laws.  users of the cz scorpion evo 3 s1 pistol arm brace adapter bear the sole responsibility for ensuring their use of the product complies with all applicable local, state, and federal firearms laws.