I can't say much about this one, because I honestly don't know! I believe it belonged to someone in my dad's family long ago. My family gained possession of it about 15 years ago.  The tester runs on two "D" cell batteries, and four "AA" batteries.  The original test leads were badly deteriorated, so they are no longer used.  I do have the original leather carrying case, which is also in bad shape.

    This tester serves as my main bench tester. It has three ranges to test resistance: RX1, RX100, and RX10,000.  Five for both AC and DC voltage: 2.5v, 10v, 50v, 250v, 500v, and 1000v.  It also has four amperage ranges: 1ma, 10ma, 100ma, and 500ma. Other than the replacement of a resistor that I cooked ( tested voltage when the meter was set on resistance!), and the batteries about once a year, this is a rather reliable unit.