57IB - Insulated Register Boot

  • Approved UL L-587 design, quivalent to other designs: L-521, 546, 550, 562, 563 and P-544
  • CRD frame and blades are 22 gauge
  • Box and collar are 28 gauge with 1.5" R-6 duct liner insulation
  • Incorporates UL 555C evaluated ceiling damper