-21 round -Compatible with all full-size, compact, and sub-compact 9mm double-stack Glock handguns -Durable, lightweight, & extremely stiff polymer construction -High visibility controlled-tilt follower -Long life stainless steel spring for corrosion resistance -Flared, easily removable floor plate -Dot matrix panel for magazine marking & identification -Magazine indicator windows on both sides of body at 10, 15, & 21 rounds remaining -Drops free loaded or unloaded