IS3 Ultra Thin Round Area & Courtesy LightThe smallest of our IS Line, the IS3 is a round, 1.75" waterproof disc ideal for stairs, pathways, courtesy lighting and livewells. Mounts simply by using VHB tape or marine caulk, the IS3 is a metal-free, non-corroding, ultra durable solution that stands up where most courtesy lights fail. A tiny 5/16" hole is all that is needed to run the centrally located wires through the bulkhead.