Tactical Force 9XP 2252108 20 Round Air Pistol Magazine 4.5mm;

Although your Umarex 9XP CO2 pistol magazine holds 20 steel BBs, consider picking up some extra mags and loading them before you hit the firing line. That way, you can just pull the trigger, change out mags and not fumble with filling and possibly spilling BBs. You know how frustrating it is when you can't get the BBs into the mag and they spill all over the floor or ground!