HVAC Round Ceiling Air Vent Diffuser, Metal Disc Valve, White Ventilation Ceiling Round Diffuser, Adjusted Clockwise / Anticlockwise Ceiling Air Vent, Regulated Disc Valve. - Amazon.com
HVAC Aluminum Supply Square Ceiling Diffuser Air Diffuser for Ventilation - China Square Diffuser, Air Diffuser | Made-in-China.com
150mm Air Diffuser Used For New Air System, Ceiling Install Air Olet For Ventilation Pipe, Air Condition, Exhuast Pipe - Air Conditioner Parts - AliExpress
IMPERIAL 4-in x 4-in 2-way Abs Resin Sidewall/Ceiling Diffuser in White in the Ceiling Diffusers department at Lowes.com