The Mistral Wall Exhaust Fan 10" with model number EF1001/MEF8210 is highly efficient. It has a built-in oil receptacle and is equipped with back flow louvers to prevent foul air from flowing back inside. It also has a built-in thermal fuse for safety.The Mistral Wall Exhaust Fan 10" is a highly efficient. It has a built-in oil receptacle and is equipped with back flow louvers to prevent foul air from flowing back inside.√e¬ø