A rather nasty continuity and voltage tester in orange plastic. No date on the meter, packaging or instructions - however probably from the 1970s or early 1980s.
This device is still in it's original box, with test leads and instruction book. The test leads have been damaged by contact with the expanded polystyrene packaging, which has caused the plasticiser to leach out of the PVC insulation.
Although the instruction book has many pages of example uses, the meter itself can only do continuity and voltages up to 3 or 15V DC. It is powered by two AA cells, and has a red LED to waste away the battery the whole time the power switch is on.
The device does still work, although is extremely limited in testing. Voltages are indicated with reasonable accuracy, although it cannot deal with reverse polarity. The continuity test is a go/no go test, no indication of resistance.
The mains socket tester is a plug containing two neon indicators, both illuminated being correct, one or none indicating some fault. This is even more limited than the more usual 3 neon tester plugs - which themselves are very poor and can often give misleading results.
The internals are connected together with pieces of wire, all hand soldered. The metal probe sockets are soldered onto a circuit board which presumably has a few resistors on the back for the two voltage ranges. All of the other components are connected together with individul wires.
Quality of construction is poor, and this item was made in the UK.
Probably not. Although it works as described, the tests are as basic as you can get. Continuity of fuses and simlar items can be checked just as easily with a battery and bulb (or a battery torch), and just measuring the voltage of a battery tells you nothing about it's condition - a reasonable load must be applied to get any kind of meaningful results.
The box, instructions and device all have large warnings about NOT connecting this item to the mains - suggesting at least one person did try this.
The instruction book can be downloaded, scanned from the original:
PDF file, 5.2MB, 26 pages
Photos of the box, device and leads are in the Tools & Equipment section.