--- All Products US Patent Nos. 9,151,106 & 9,518,422 | Canadian Patent Nos. 2846726 & 2939255 ---
THE CROWN FIRE DOOR STOP SYSTEM IS TESTED AND LISTED WITH UL!
The Crown Fire Door Stop System is UL approved for excessive clearances on wood and steel fire doors.The Crown Fire Door Extension has been UL approved to correct excessive undercuts on wood and steel fire doors. All Crown accessories are fire-rated for up to 90 minutes. Applying these products does not increase or decrease the fire door assembly's existing fire rating.
No other products are UL approved, with a 90-minute rating, specifically for excessive clearances.