Cross Armory Glock 3 Piece Kit contains Dimpled Pin Set, Extended Magazine Catch and Extended Slide Lock. The Slide Lock and Pin Set is made of 4140 Steel, the Magazine Catch is made of Aluminum. Does not intefere with gun holster. Compatible with Glock 17/19/20/21/22/23/26/27/29/30/31/32/33/34/35/40/41 Gen4.