Clear Plastic Thermostat Guard - See Thru - Solid Base - 8.25" x 5.37" - Extra Large - With Lock & Key 8" Diameter + Product Details Size -

+ Product Details Size - 30"w X 18"h is the size for the duct opening measurement only

the actual front end outer dimensions are 6" in diameter

Looks like it was just waxed

this guard fits almost any thermostat and blends seamlessly into any setting

Clear Plastic Thermostat Guard - See Thru - Solid Base - 8.25" x 5.37" - Extra Large - With Lock & Key 8" Diameter + Product Details Size -+ Product Details Universal Fit Accommodates almost any thermostat with dimensions of 8 1 4" H x 5 3 8" W x 3 1 2" D. Durable Construction Made from high quality, high impact clear plastic for long lasting performance. Locking Security System Features a built in eight tumbler lock and a supplied key to prevent tampering and maintain consistent temperature settings. Easy Installation Comes with all necessary installation screws for a quick and hassle