A neon single pole voltage indicator, which is electrically identical to a neon screwdriver.
Very similar in construction to the neon screwdriver devices that are available, although this one has no screwdriver tip.
As most 'neon screwdrivers' are entirely useless as screwdrivers, the lack of a screwdriver tip isn't a problem here.
The metal probe tip is covered with what looks like blue heatshrink insulation.
A metal cap and clip provide the conductive connection to the user's finger.
Neo-Maintest Electrical Fault Finder
'The Electricians Mate'
Tests 100 to 700 volts AC
User safety is only provided by the resistor.
Rather bizarre that spare parts were available, including the neon lamp, resistor and spring.
No date is given, however the telephone number begins 01 which is after PhONEday, 16 April 1995.
Three sides have text as shown in this and earlier images, the fourth side of the box is plain red.
Fully guaranteed. Made in England by Neo Electrical Industries, High Peak, SK23 7EE.