I know what the promag mod is and thats done too but its something else there is a mod attached to the front of the valve where you normally screw your 90 degree adapter for macro line.The it goes into the front about 1" up and i have no idea what its for.predator paintball was the shop ran by marcus davies captain of the preds and the valve mod is called the promag mod done by orginal jon sosta and the preds i believe it involved drilling holes into the valve allowing more air into the valve chamber allowin quicker recharging of the air chamber I think as its along time since i had mine