3 Hour Out Of Air Fire Door Grille 2663-36X22 Step Down Ceiling Diffuser Standard Features 1” rim size

Standard Features 1” rim size (2” larger than nominal duct size / order size) 14 gauge steel construction Countersunk mounting holes for a flush appearance 1-27/32” Wide x 11/32” High slots on staggered centers

Locking screw to hold damper in place

All steel construction

stair risers

Spiral pipe diameter must be 4” larger than Height of the duct opening

3 Hour Out Of Air Fire Door Grille 2663-36X22 Step Down Ceiling Diffuser Standard Features 1” rim sizeh3. Standard Features * 2661 Square or rectangular fire door for vertical mount only. Maximum dimension 60x60. For damper free area chart A click here * 2663 Out of Airstream fire door. Square or rectangular for vertical mount only. Maximum dimension 60w x 52h. For damper free area chart B click here * 2665 Round fire door for vertical mount only. Available 4" thru 52" round. * 3 hour rated * UL and California State Fire Marshall approved * 4 1 4"