Glock 20 Gen4 10mm Auto 4.6 Inch Barrel Black Finish Fixed Sights 10 Round. Glock system adapted to the 10mm auto cartridge. Delivers accuracy and maximum durability while controlling recoil. Features fixed sights, interchangeable backstrap, revisable magazine catch and Dual recoil spring. Safe Action trigger system with three safeties. Right hand, hexagonal barrel rifling. Tenifer surface treatment process for barrel and slide.