4" 3 Hour Vertical Mount Fire Door 2661-20X20 past 12 months Standard Features * Round 1-1/2

Standard Features * Round 1-1/2 hour fire damper * Horizontal or Vertical installation * UL and California State Fire Marshall approved * Damper construction meets NFPA 90A requirements * Stainless steel curtain * 16 gauge steel frame * UL listed fusible link

Retainer cables are provided on sizes 12" and larger to allow the inner cones to hang securely while adjusting the diffuser

Concealed mounting holes

904 - Double Deflection Adjustable Aluminum Blade Grille For a 18" x 6" Duct Opening   (front blades parallel to shortest dimension)

Standard Features * 1/2" x 1/2" x 1/2" aluminum lattice face *

4" 3 Hour Vertical Mount Fire Door 2661-20X20 past 12 months Standard Features * Round 1-1/2h3. 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"