What a great old analog meter, Triplett 630. This is the older version and is from some time in the 50s I believe. The case is bakelite, or polyoxybenzylmethylenglycolanhydride, which is an early plastic material made of phenol and formaldehyde.
It is called a VOM because it measures volts, ohms, and milliamps. Well, regular amps too.
I bought this on eBay $20 untested and it’s actually really accurate to its testament but a few resistors were drifted and were replaced. It takes two batteries for the ohms ranges, a 1.5V for the X1 and X10 range and a 30V for the X1,000 and X100,000.
30V batteries are not available anymore so you have to hack one together with three 9V and two 1.5V in series for 30VDC, and the wonderful old VOM is ready for use again. Resistance measurements on this meter are impressively accurate compared to my Fluke DMM.