Flukers Screen Covers are made of durable metal to provide a secure habitat for your reptile or amphibian. Its durable construction withstands high temperatures and heating devices while allowing excellent air circulation and reducing growth of mold and bacteria.Durable metal construction withstands high temperatures from heating devicesMesh screen allows air circulation to minimize growth of mold and bacteriaHelps provide a more secure and stable environment for reptilesFlukers Screen Covers are sized to fit most standard terrariumsFlukers Screen Cover Dimensions:10 gallon (10"L x 20"W)20L/29 gallon (12"L x 30"W)30 gallon (12"L x 36"W)40 gallon (18"L x 36"W)