Pachmayr Mag Sleeve adapts full-size magazines for use with compact handguns in many popular models. The sleeve allows you greater shooting capability by increasing the gun's grip size and capacity with additional rounds. Carry your compact pistol with a standard magazine when concealment is important, or insert a high capacity magazine fitted with your Pachmayr Mag Sleeve when the situation calls for it. Compatible with your Glock 29/30 with 20/21 mags.