ZEV Technologies Extended Base Pad For Glock, Black Finish, Add 5 Capacity on 9mm, Add 4 Capacity on .40 Cal, Additional Power Spring Included, Glock Magazine Not Included, Fits 17Rd Capacity Glock 9mm .40 Magazines, Does NOT Work w 10Rd or 15Rd Capacity Magazines BPAD EXT GLK 5 B