Diameter is 105mm at base; the actual lens/light is around 84mm in diameter. Depth overall is 30mm.
The instructions say: 'Your interior lamp has three positions. In switch position 1, you can switch on the interior lamp by hand [ie: by twisting the lens/light]. In position 2. the interior lamp is switched on when the door is opened, e.g. by means of a door contact. '
There are a couple of diagrams illustrating these points and the wiring if you're using a door contact. When we fitted the others in our boat, we switched them on manually. This pair were surplus to our needs.
Hi Wilmot - these are the smaller Hella lights and I was hoping they were the larger ones (145mm) to replace some lights in our sea-berth cabins....Thanks anyway.