Pearce Grip Grip Extension, Fits Glock Gen 4 26/27/33, Black Finish PG-42733 These units replace the magazine base plate and internal floor plate. They will add two rounds to the Glock M26" one round to the Glock M27 and M33 and no rounds to the Glock M39. These units will add 5/8" additional length for better control and comfort.