CHOOSING and ORDERING PANEL METERS
Once you've decided on the style and size you want, there are two important ingredients needed to order the panel meter that best suits your application - input value and scale.
Typical input values can be 0-5AAC, 0-50mV, 0-20mA, 4-20mA, 0-750VAC, 0-10VDC and a host of others too numerous to mention here.
Scales don't necessarily indicate the same values as the inputs. In fact, they rarely do. They do when the input is 0-750VAC and the scale reads 0-750VAC. Most of the time, however, you'll probably have something like 0-5AAC input and a scale which reads 0-100AAC or 0-150% or perhaps 4-20mA in and a scale of 0-5000FPM (feet per minute) or 1000 GPH (gallons per hour). You get the idea.
If you're ordering a DIGITAL panel meter, then you'll also have to specify the auxiliary voltage, usually 120VAC, so that the display will light up.