PMI HP = red(4500/5000psi) black (3000psi) , LP = blue,
same for crossfire
read what is written on the regulator
or ask someone in a shoip if buying new
make sure whatever LP system you use is fast recharge
there can be drop off issues with inferior systems.
max flos are pretty good hence, no problems
i just made the general statement that a HP is the safe bet, and more than likely unless you buy an angel, you can use HP Presets on most guns with no problem