The KRISS Mag-Ex Kit 2 is the ultimate capacity extending base plate for your factory standard Glock magazines. The KRISS Mag-Ex Kit 2 is made up of the extended baseplate, outer sleeve, and extended spring, constructed of durable and lightweight reinforced composites. This Mag-Ex Kit 2 is designed for standard capacity G 21 for an overall capacity of 30 rounds for the KRISS Vector, Glock handgun, and Glock magazine-compatible pistol caliber carbine. *Incompatible with reduced capacity 10rd magazines.