Abstract: A test set, as used for indicating line conditions and line identification for telecommunication cables for example, has a casing formed from two identical mouldings. A rib and groove seal is provided for the mating surface by forming a rib on half the mating surface and a groove on the other half. Laterally extending webs form a channel in which the leads of the test set are wound when not in use. Ears on the webs extending towards each other form constrictions which maintains the leads in the channel. At the top of the casing, arcuate webs provide a protected region in which are situated a toggle switch and indicator lamps. Inside the casing, formations hold a printed circuit board and define a compartment for a battery.