SM -- RG303 (50–80 psi)
MD -- RG305 (80–110 psi) 
LG -- RG310 (110–140 psi)
 
Hookah
The term “hookah” refers to the breathing gas being supplied from the surface.
The term “hookah” refers to the breathing gas being supplied from the surface.
RG303 - uses an intermediate pressure of 50–80 psi (3.5–5.5 bar) Often used with compact specialty compressors
RG305 - uses an intermediate pressure of 80–110 psi (5.5–7.5 bar)Often used with larger, commercial grade, specialty compressors
RG310 – uses an intermediate pressure of 110–140 psi (7.5–9.5) bar Typically used with scuba cylinders left on the surface with a long hose
A robust, over-built design for commercial-style use
Venturi deflector to prevent accidental free flows
Simple and easy to service
Choose From: 
50 to 80 PSI, 80 to 110 PSI or 110 to 140 PSI