Glock magazines are known for their reliability and durability, so it makes sense that KRISS didn't try to reinvent the wheel. Pairing a factory Glock magazine with the KRISS MagEx2 extension kit results in 33 rounds of 10mm at your fingertips, ready to be sent downrange. On The back of the magazine are numbered witness holes, so you'll never lose track of how many rounds you have left. KRISS recommends using a magazine loader such as the maglula UpLULA to insert those last few rounds. This magazine is black in color.