Designed for laser welding setups, these quartz protective lenses measure 18 mm in diameter and 2 mm thick, supplied as a five-piece set of lenses only. The quartz construction provides a clear, durable barrier for shielding the optics in a laser welding head, and the modest thickness keeps the lens compact within the assembly. Replacing these lenses in sets of five allows operators to keep spares on hand for routine maintenance.