Adjustable pattern slot diffusers

Adjustable plenum slot diffusers for T-bar lay-in or hard ceiling applications, or for mounting on round duct.

Standard Construction

  • 1/2", 3/4", 1" OR 1-1/2" wide slots
  • Up to 10 slots wide
  • Up to 72" long in a single section
  • Supply and return units
  • Air pattern adjustable through 180 degrees
  • For use with 15/16" or 9/16" T-bar, hard ceiling or round duct mounting


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K Series Slot Diffuser – standard T-bar or hard ceiling
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K Series Slot Diffuser – 9/16" Fineline® T-bar ceiling
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RK Series Slot Diffuser – Round Duct
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KEES, Inc.
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Surface Mounting Frame
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KEES, Inc.
KEES, Inc.

Other Information

Installation and Operating Manual (PDF)

Options & Accessories

  • All white face
  • Internal duct liner insulation
  • Internal or external foil faced insulation
  • Elastomeric thermal insulation
  • Inlet damper with manual quadrant lock
  • Face operated dampers
  • Two-slot units with or without center tee
  • Side Tees
  • T-bar clips
  • Surface mounting frame for use in hard ceilings
  • Tegular ceiling mounting
  • Spline ceiling mounting
  • Cross notch for cross tee
  • Integral supply and return plenums
  • Top inlet collar
  • Mitered corners
  • Diffusers without plenum (3-1/2" high with open top)
  • Multiple collars
  • Non-standard collars
  • Non-standard unit heights
  • All aluminum construction
  • All stainless steel construction


  • 24-gauge galvannealed steel plenum
  • Extruded aluminum air pattern controllers with a felt edge
  • Extruded aluminum Tees and surface mounting frames
  • ½" fiberglass duct liner internal insulation


  • Black face and interior
  • Off-white Tees