You're confusing input pressure and operating pressure. And even then, you could further break it down into firing pressure and cocking pressure. Input pressure is irrelevant, you could run a LP marker with an 850 psi output tank, so long as your secondary regulator is adjusted properly. The new style mini regs are just designed for LP input, so they don't handle HP very well (sometimes they can't cut it down far enough and your velocity won't come down). From your tank, air heads up to the mini-reg, where it gets cut down even further to whatever pressure is giving you your desired velocity (between 150 and 250 psi). Lest we forget, that a portion of the air stored behind the valve (the 150-250 psi) gets directed to the LPR, where it gets cut down even further to anywhere between 50 and 80 psi (the pressure necessary to move the piston in the ram back and forth), then goes to the solenoid to operate the ram. So as you can see, the 05 Speed is indeed a very low pressure marker.