This is the sleeve for the Sig Sauer 220 magazine, to make it fit into a p245 model comfortably. Marked Sig Sauer
Use:
The 2 piece X-GRIP slides over the P220 plastic floorplate and snaps together for a secure fit. No tools are required. Once installed, the XGRIP completely encloses the extended magazine and floorplate. Compatible with SIGSAUER factory magazines and Act-Mag/ Novak mags with the plastic basepads.