Attwood 66400-3 Stainless Steel Clam Shell Vent This clam shell vent is designed to provide a seal and offer splash protection for vent holes as well as wire and hose openings. This Clamshell vent cover holes up to 1-12 in diameter and hose or wire up to 916 in diameter. Constructed from stainless steel this vent boasts durability and corrosion resistance. This vent cover has 3 mounting holes that require 6 fasteners not included. These clamshell vents are sold in pairs of 2. Product Specificati