Remarkable for its accuracy and light recoil, the GLOCK 21 Gen4 delivers the power of the 45 Auto round with high magazine capacity. The Modular Back Strap system makes it possible to instantly customize its grip to accommodate any hand size. The reversible magazine catch makes it ideal for left and right-handed shooters The Gen4 system is the perfect complement to the 45 Auto caliber cartridge. Includes three 13-round magazines.