# Helhom 4 in. x 25 ft. Insulated Flexible Duct R4.2 Silver Jacket, Flexible Ductwork Ducting, Venting for Ventilation System

**Brand:** [Helhom](https://shop.coreranger.com/brands/Helhom)
**SKU:** 78621_BHKFR
**Price:** $108.97 · in stock
**URL:** https://shop.coreranger.com/product/helhom-4-in-x-25-ft-insulated-flexible-duct-r4-2-silver-jacket-flexible-ductwork-ducting-venting-for-341715497

## Specifications

| Spec | Value |
|---|---|
| Color | Silver |
| Model # | 78621_BHKFR |
| Material | Rubber |
| Insulated | Yes |
| Pack Size | 1 |
| Internet # | 341715497 |
| Returnable | 90-Day |
| Store SKU # | 1015513598 |
| Insulation R-Value | 4.2 |
| Product Width (in.) | 4 in |
| Product Length (in.) | 300 in |
| Wall Thickness (in.) | 0.04 |
| Maximum air flow (CFM) | 300 |
| Product Diameter (in.) | 4 in |
| Certifications and Listings | No Certifications or Listings |

## Description

This 4 in. insulated flexible duct features a durable construction with thickened aluminum foil and high-strength elastic spiral steel wire. The middle layer is glass fiber insulation, offering high temperature resistance up to 454℃, acid and alkali resistance, and flame retardancy. Its fluffy internal structure and high density reduce noise by up to 85%, while the flexible design allows arbitrary bending without rigid elbows. The aluminum foil is self-sustaining, maintaining flatness inside to lower wind resistance. Suitable for high, medium, and low pressure ventilation systems without corrosive gases, it works well in central air conditioning HVAC, fresh air, and mechanical equipment recovery systems.

• R-4.2 insulation for high thermal performance
• Durable aluminum foil and elastic steel wire construction
• Flexible design allows bending without rigid elbows