Okay - I have sourced a guage for us.
Dial Size: 1.5 inches
Range 0 to 600 psi
Connection Size 1/8" NPT, (Location - off center - back)
Smallest Graduation: 20 PSI
Accuracy: +/-3%, -2%, -3%
Case Material: Steel
Case Color Black
Socket Material Brass
Tube Material Bronze
Lens Material Glass
Operating Temp. Range (F) -40 Degrees to 120 Degrees
Manufacturers Warranty Length 1 Year
This will be perfect for low pressure tanks - and all regs out there.
This means you are +/- 2% when dialing in any reg in the CCM line!
I think this is a good choice.