Replaces the magazine floor plate and factory magazine spring adding grip length and capacity. Installation of this component requires the removal of the detachable magazine well.This extension will increase the factory 10mm magazines originally 10 or 11 rounds to 12 rounds.(Keep in mind you may be removing a the factory plus one baseplate.)This extension will increase the factory 45 ACP magazines originally 9 or 10 rounds to 10 rounds.(Keep in mind you may be removing a the factory plus one baseplate.)Fits XDME 10mm and 45ACP as well as all XD series compact/subcompact magazines in 10mm and 45.