Design/Construction
Forged brass body & housing cap 
2.5" (63.5 mm) gauges - brass (6000 lb high  pressure, 600 lb and 1000 lb low pressure)
Cartridge type seat assembly with PCTFE seat 
Diaphragm - stainless steel
External self-reseating relief valve
CGA 540, 580 346 have a maximum inlet pressure of 3000 psig 

Dimensions
W x H x D : 7.5" x 6" x 5" (190.5 mm x 152.4 mm x 127.0 mm)
 
 
Weight
5 lb 7 oz (2.47 kg)
 
Performance
Maximum inlet : 5500 psig 
Outet preussure ranges : 350 and 550 psig
Inlet port : 5/8"-20 UNF (M)
Outlet fitting : 1/4" Swagelok-brass
Temperature operating range : 0-140 ํF