Great light bulb cufflinks for people with bright ideas. Lights up with a white light when the silver button on the back is pressed.
The round back of these cufflinks contains the battery - it does not remove to go through the sleeve (unscrewing it will reveal the wires). The thickness of it does mean you need to firmly push it through the button hole and may make it unsuitable for shirts with smaller holes.
Dimensions: 21mm x 12mm x 12 mm (approx.) Weight per cufflink: approx. 7g (medium)