Milwaukee®, 31-01-1800, Cartridge Holder, For Use With: 2640-20, 2641-20, 2641-21CT, 2642-21CT, 2643-21CT, 2641-20 (D15A), 2641-21CT (D15A), 2643-21CT M18 Cordless Caulk and Adhesive Gun, 2640-20 (D15A) M18 caulk gun, 2642-21CT (D15A), 2641-20 (D15A), 2641-21CT (D15A), 2643-21CT (D15A)