For Use In Existing Ceilings. Integral Flange and Exclusive Locking Bars Permit Quick Mounting In 1/2 In to 1-1/2 In Thick Ceilings. Ul & Cul Listed For Damp Locations. Ic/Non-Ic Peel Away Label For Trims. When Used With P8593-01 Gasket Kit, This Housing Is Certified to Meet Astm E283 Air Tight Requirements When Installed Properly Per Instructions.