Pressure Relief Horizontal Air Up 3520-18X12 Smoke-Fire Damper Standard Features * Extruded aluminum

Standard Features * Extruded aluminum construction * 45 fixed blades parallel to longest dimension * Margin edges are 7/8" projection for baseboard installation * Countersunk mounting holes for flush appearance with color matching Phillips posi-drive screws * Soft White Options * 1100FF - flush frame * Fractional and odd dimension sizes * Standard Color

Standard Features *Surface mount return air grille * 45 fixed blades parallel to longest dimension * Countersunk mounting holes for flush appearance with color matching Phillips posi-drive screws * Soft White Options * 935 O - recessed screwdriver operated opposed blade damper * No Labor Collar (square sizes only) * 900 T - T-Bar mount * 905 HD - reinforced construction * 905 IS - insect screen * 1335-1338 Series - stainless steel version * Tamper proof screws

Round Bowtie Damper

2" thin-line roll formed out-of-airstream frame

Pressure Relief Horizontal Air Up 3520-18X12 Smoke-Fire Damper Standard Features * Extruded aluminumh3. Standard Features * 3510 Vertical mount * 3520 Horizontal mount air up * 3530 Horizontal mount air down * Designed to open with negative or positive pressures for intake or exhaust air * Felt edge blades to hold noise to a minimum * Aluminum construction * Blade to blade linkage * 1 4" pivot pins in nylon busings * Maximum size 24 x 24 * Mill finish h3. Options * Sleeve variations * Mounting flange * Adjustable counter balance to adjust various