One piece polymeric blower wheel. White polymeric grill. Dimensions: 16-1/2 in x 10 in Two - 250 watt maximum, type R40 bulb, medium base infrared lamp to deliver silent heat to the room and is rated type IC for ceilings insulated to R-40, bulb (not included). Plastic collar for 4 in duct connection comes complete with built in non-metallic back draft damper for quiet operation. UL listed. HVI2100 certified.