If you're using the Beretta PMX SMG airsoft gun you're going to want to carry some spare magazines to the match. This PMX green gas magazine holds 48 6mm airsoft BBs and fills up with Green Gas through an easily accessible fill port. And just in case, it comes with an extra fill port o-ring to make sure you're always ready for the airsoft field. To load the Beretta PMX airsoft magazine, remove the mag from the gun, pull the BB follower down until it locks in place, and then load it with 6mm BBs, of course, a speedloader will make this easier. Once filled, release the BB follower. Now, to charge the mag with green gas turn the magazine upside down, and locate the fill port. Invert your green gas can, meaning turn it upside down, and press the needle of the can into the fill port. Hold it in for a few seconds, release it, then repeat. Do this until the green gas spews out a little then you're done. Use .25g BBs for best results with the Beretta PMX.