This device has 4 lights: a green one, a red one and two yellow ones.

The green and the red light indicate if the circuits are correct.

The two yellow ones go on for approximately 1 sec. at each interruption of the relevant circuit and are therefore useful to show micro-breaks.

Power supply: 12V battery included (common radio controls battery A23 or VR22 type).

Sturdy case of extremely small dimensions: 3.8 x 5.5 x 2.9 cm.