These clamshell vents can be used to seal and splash-proof openings for wire, hose, etc. Also ideal for locker vents. Made from stamped stainless steel. Requires 3 #6 fasteners for installation. Skin packed. Small Clamshell Vent - Covers holes up to 3/4 in. Hose or wire up to 7/16 in. Dia. 1 in. L x 1-3/4 in. W x 7/16 in. H. What is the Attwood difference, Value and ingenuity.