4 1/4" Vertical Mount Fire Damper 2633-48X18 Residential Registers & Grilles Spiral pipe diameter must be

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

with 75% free area

CB20 - two way

Maximum dimension 60x60 single

Directional volume diffuser with 4-way removable core

4 1/4" Vertical Mount Fire Damper 2633-48X18 Residential Registers & Grilles Spiral pipe diameter must beh3. 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