Visible lens diameter is 3.5in.. The overall OD of the rim is about 4.25in.. One has a plain shell and the other has two grooves for a ball mill look just the the existing Buffalo headlamp and spotlights. There are two different rims - one is plain, the other is hooded (has a visor). Headlampsare equipped with a H4 12V 60/55W bulb. Sold each.