4" 3 Hour Vertical Mount Fire Door 2661-36X30 Smoke-Fire Damper 3/4” Wide x 3/4” High

3/4” Wide x 3/4” High square holes

Standard Features * 1/2" spaced vision-proof dual angular louvers for strength and maximum free area * Margin edges are 7/8" projection for baseboard installation * Soft White with color matching screws Options * 1133 - 1/3" spaced dual angular louvers * 1175 - added mullion stiffeners for greater strength * Standard Color

For damper free area chart B click here * 2665 - Round fire door for vertical mount only

Multi-Shutter Damper standard on 6" widths and larger

4" 3 Hour Vertical Mount Fire Door 2661-36X30 Smoke-Fire Damper 3/4” Wide x 3/4” Highh3. 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"