The Mistral Wall Exhaust Fan 12" with model number EF1201/MEF8212 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 12" 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.√e¬ø