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Thermaflex 051712000003 - 12" M-KC R4.2 Insulated Flexible Air Duct

Item: MKC25R4.212
MFR: 051712000003

This product is no longer available for purchase.

Comparable Products


M-KC Features and Benefits:
  • Underwriters Laboratories listed, and complies with NFPA Standards 90A and 90B.
  • Core material will not support mold and mildew growth.
  • Highly resistant to rust and corrosion.
  • Fully lined for efficient air delivery.
  • Large diameter, heavy, spring steel wire helix assures dimensional stability, resists mechanical abuse and provides more efficient air delivery.
  • Bi-directional reinforced metallized jacket resists tearing - reduces chance of damage to vapor barrier.
  • Heavy woven and coated fiberglass cloth core assures quiet performance. Core is almost impossible to puncture or tear. No more concern about fiber in the air stream or loss of conditioned air.
  • Uniquely constructed core will not unravel when cut.
  • All components of M-KC are self-extinguishing and will not support flame (see oxygen index figures under application and engineering data). Core will not deteriorate in a fire until the temperature reaches the melting point of glass.
  • "Outward cast" of helix keeps duct core from shrinking up inside insulation and jacket, resulting in less waste.
  • Heavy woven and coated fiberglass cloth core will not "blow-out" and eliminates costly call-backs.
  • Lower installed cost.
  • Available through broad national distribution.
    Lifetime Warranty:
    Thermaflex warrants that the M-KC Flexible Air Duct will be free from defects in materials and factory workmanship for life. This warranty covers the flexible duct, materials and labor. This warranty applies only to ducts properly installed in accordance to Thermaflex's written installation instructions and under conditions specified in published performance data. Thermaflex shall not be liable to buyer or any third party for any special, secondary, incidental or consequential damages however arising.


NameThermaflex 051712000003 - 12" M-KC R4.2 Insulated Flexible Air Duct
Gemaire Item NumberMKC25R4.212
Manufacturer Product Number051712000003
SKU - PIM Number1408712641191
ERP Number358261
Unit of MeasureEA
Weight23.1 Pounds (Lb)
Length15.1 Inches (In)
Width12.0 Inches (In)
Height15.1 Inches (In)
Country of OriginUSA
Jacket MaterialReinforced Metallized Jacket
Vapor Transmission0.05
ApplicationAir Distribution
ColorSilver, Pink
Comments/NotesUL Listed - USA & CAN
Core MaterialWoven Fiberglass
Fire RatingNFPA Standards 90A and 90B, Max Flame Spread 25. Max smoke developed 50
Inside Diameter12"
Maximum Air Flow6000 FPM
Maximum PressurePositive = 6" (4-10" ID) 10" (12"-16" ID) Negative = 2" (4-16" ID)
Maximum Temperature250°F (121.1°C)
Operating Temperature-20°F to 250°F (-28.8°C to 121.1°C)
Pressure RatingWG - Positive 16 inches (4"-10" ID), 10 inches (12"-16" ID) - Negative: 2 inch (4"-16" ID)
Size12" x 25'
Warranty OfferedYes
ComplianceNFPA 90 A and 90 B
UL ListedYes
UL RecognizedYes
GEM - Case Quantity


Parts List