Answer:
A standard regulator will receive 800-900 psi and then stabilize the output at a psi near the 800-850 mark (adjustable)
A LPR will receive 800-900 psi and then stabilize the output at 140-230 psi (adjustable)
The LPR is only used on guns that use low-pressure air internaly and will be found on guns in the $400+ price range.