Hy-C, Dryer VentGuard, Made Of 100% Stainless Steel, Durable Polyester Powder Coasted Finish, Prevents Small Animals From Nesting In Exhaust Vents, Keyhole Attachment Allows For Removal To Clean The Vent, Easy To Install Over 3" Or 4" Dryer Or Bathroom Vent Holes, Will Not Rust Or Corrode.