4" Horizontal/Vertical Mount Fire Damper 2634-18X8

h3.Standard Features * 2633 - Square or rectangular out-of-airstream fire damper for vertical mount only. * 2634 - Square or rectangular Spring actuated (6) out-of-airstream fire damper for horizontal or vertical mount. * UL and California State Fire Marshall approved * 4-1/4" standard frame style * Maximum dimension 60w, 52h * Interlocking steel roll-formed blade (3) with roll-formed frames (1) * Blade lock (5) * Damper manufactured from corrosion tested galvanized mild steel (G-90) * Self locking corner (4) * 165° replaceable fusible link (2) h3.Options * Sleeve variations * 304 stainless steel construction * Fractional and odd sizes available h3.Installation Instructions * UL approved installation instructions