This is compatible with factory Glock 21 magazines. 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.

Combining the Mag-Ex Kit 2 with the factory standard Glock magazine body and follower is a perfect match of reliable feeding, toughness, and aesthetics for the KRISS Vector.