Deflecto Round Ceiling Diffuser, Adjustable, Requires No Studs for Installation, 4 Inches Dia., White (TFG4) Create more comfortable spaces by distributing hot or cold air with this round air diffuser, ideal for suspended ceilings Add heating/cooling air vents to your room addition, basement, garage and more Each 4" diameter installation is designed to handle areas up to 60 square feet Easy to adjust and install! Unique locking feature requires no studs for installation For central forced air heating and cooling applications