Spring-loaded aluminum back draft damper prevents drafts from entering back into the room. Metal 8 in round diameter housing, vents directly to outside, includes spring-loaded aluminum back draft damper for maximum air flow. Direct to outdoor exhaust design eliminates the need for ducting. White polymeric grill. Dimensions 11-1/2 x 11-1/2 in. One-piece polymeric wheel. UL listed. HVI2100 Certified.