MASTERPIECE ARMS DEFENDER a 5.7x28mm a 16 barrel a 20 round a Semi Automatic a Cerakote finish - burnt bronze standard a Side Cocker Scope Mount a One (1) Muzzle Brake a Thread Size 1/2 x 28 a American Made a Ships in Gun Case a Lifetime Guarantee a MPA Low Profile Buttstock a MPA Aluminum Extruded Quadrail a Adjustable Front Sight a Fully Machined Aluminum Frame a Fully Machined Aluminum Grips a Accepts both FN57 and Promag 57 Magazines