---
product_id: 325699185
title: "3M Aluminum Foil Tape 3340, 2.5\" x 50 yd, 4.0 mil, Silver, HVAC, Sealing and Patching Hot and Cold Air Ducts, Fiberglass Duct Board, Insulation, Metal Repair"
brand: "3m"
price: "$63.79"
currency: USD
in_stock: true
reviews_count: 13
category: "3 M"
url: https://www.desertcart.us/products/325699185-3m-aluminum-foil-tape-3340-2-5-x-50-yd
store_origin: US
region: United States of America
---

# Waterproof & vapor seal -40°F to 300°F temp range 4.0 mil thick foil backing 3M Aluminum Foil Tape 3340, 2.5" x 50 yd, 4.0 mil, Silver, HVAC, Sealing and Patching Hot and Cold Air Ducts, Fiberglass Duct Board, Insulation, Metal Repair

**Brand:** 3m
**Price:** $63.79
**Availability:** ✅ In Stock

## Summary

> 🔧 Seal it like a pro — the tape that keeps your airflow flawless!

## Quick Answers

- **What is this?** 3M Aluminum Foil Tape 3340, 2.5" x 50 yd, 4.0 mil, Silver, HVAC, Sealing and Patching Hot and Cold Air Ducts, Fiberglass Duct Board, Insulation, Metal Repair by 3m
- **How much does it cost?** $63.79 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.us](https://www.desertcart.us/products/325699185-3m-aluminum-foil-tape-3340-2-5-x-50-yd)

## Best For

- 3m enthusiasts

## Why This Product

- Trusted 3m brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Effortless Application:** Pressure-sensitive acrylic adhesive with an easy-release liner means quick, precise installation every time—no mess, no fuss.
- • **Certified Quality Assurance:** UL181A-P and UL181B-FX listings guarantee professional-grade performance trusted by HVAC pros and industrial experts alike.
- • **Industrial-Grade Durability:** 4.0 mil aluminum foil backing ensures unmatched strength and longevity for demanding HVAC and metal repair tasks.
- • **Moisture & Chemical Barrier:** Waterproof and resistant to dust and chemicals, providing a reliable vapor seal that protects your systems.
- • **Extreme Temperature Resilience:** Operates flawlessly from -40°F to 300°F, making it your go-to tape for both freezing winters and scorching summers.

## Overview

3M Aluminum Foil Tape 3340 is a premium 2.5" x 50 yd HVAC sealing tape featuring a robust 4.0 mil aluminum foil backing combined with a pressure-sensitive acrylic adhesive. Engineered to withstand extreme temperatures from -40°F to 300°F, it offers superior moisture, dust, and chemical resistance. Certified to UL181A-P and UL181B-FX standards, this tape delivers a long-lasting vapor seal ideal for duct closure, insulation, and metal repair applications across industrial and residential settings.

## Description

When sealing ducts and other surfaces for heating, ventilation and air conditioning systems (HVAC), it's essential to have a strong, long-lasting foil tape that can stand up well to hot and cold temperatures. The 3M Foil Tape 3340 has the combination of 2.0 mil aluminum foil backing and strong, pressure sensitive acrylic adhesive that gives our tape a superb operational temperature range of -40°F (-40°C) to 300°F (149°C) making it ideal for sealing rigid fiberglass duct boards and flexible air duct systems. The foil backing also serves as an excellent barrier against moisture, dust and many chemicals — making it strong, durable and long-lasting. The very low moisture vapor transmission rate makes the tape a good sealant and the acrylic adhesive supplies superior temperature and UV resistance to give you a strong, lasting and reliable bond. It also has an easy releasing poly coated kraft paper liner to protect the adhesive and keep the tape ready for use. 3340 tape meets requirements for UL 181 A-P and UL 181 B-FX Listings as a measure of reliability and quality standards. 3M Foil Tape 3340 is used in a variety of applications including heating ventilation air conditioning (HVAC), duct closure, vapor seal on reinforced fiberglass duct board, rigid fiber glass duct board, and flexible air ducts and air connectors across a number of industries, including: transportation, specialty vehicle, metalworking, construction, automotive, military and government, general industrial, MRO, electronics and aerospace.

Review: Genuine 3M Quality - Genuine 3M product, Quality as expected, Easy to cut to the correct size before placing it, with the backer paper protecting the sticky side, but sticks were you put it. I used this to patch some gaps in aluminum ductwork directly below the furnace output, and it has stayed stuck through both Heating and Cooling cycles.
Review: The high quality aluminum “duct” tape - This is the good one, this stuff is tough too. I always like to have some on hand for projects around the house. You’d be surprised how useful this tape can be once you have some on hand. My dad always used this at work (HVAC) so I’ve learned over the years how to properly use this tape to make my A/C more efficient. This is great for taping up cracks around your furnace or condenser coil. You can also use it to tape the chill line near the outside unit if your lines have areas that are exposed, or if there are places that are beginning to be exposed. You can buy cheaper brands, but there’s some things you shouldn’t buy off brand, and this one of them. Buy the legit 3M tape, it’s worth it. It’ll save you money in the long run as you won’t constantly be having to patch up previous applications. I’m not a certified HVAC tech, but after riding with my dad from elementary school until I graduated, I do know to highly recommend this specific tape. This can also be used on small windows, such as the small window panes on some front/back doors, and for lots of other applications. If you’re a homeowner, I truly believe a roll of this tape should be in your home tool box.

## Features

- VAPOR SEAL TAPE: 2.0 mil aluminum foil backing (4.0 mil total thickness) with a strong, pressure sensitive acrylic adhesive is ideal as a vapor seal tape for duct closure.
- HOT AND COLD TEMPERATURES: Combination of a foil backing and acrylic adhesive gives this tape a superb operational temperature range of -40F-300F (-40C-149C).
- EASY RELEASING LINER: Poly coated kraft paper liner protects the adhesive and keeps the tape ready for use.
- LONG LASTING: The foil backing serves as an excellent barrier against moisture, dust and many chemicals - making it strong, durable and long-lasting.
- APPLICATIONS: Heating Ventilation Air Conditioning (HVAC), duct closure, vapor seal on reinforced fiberglass duct board, rigid fiber glass duct board, flexible air ducts and air connectors.
- Listed for both UL181A-P and UL181B-FX

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B091QCSQXK |
| Adhesive Format | pressure-sensitive |
| Adhesive Location | SINGLE_SIDED |
| Adhesive Side Count | 1 |
| Best Sellers Rank | #2,556 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #36 in Duct Tape |
| Brand | 3M |
| Color | Silver |
| Compatible Material | Aluminum,acrylic,glass,metal,kraft Paper |
| Date First Available | April 5, 2021 |
| Foil Thickness | 4 Mils |
| Global Trade Identification Number | 00638060401323 |
| Item Weight | 0.8 ounces |
| Item model number | 40132 |
| Manufacturer | 3M |
| Material | Acrylic |
| Number of Items | 1 |
| Product Dimensions | 2.5"L |
| Recommended Uses For Product | Sealing |
| Size | 2.5 inches x 50 yards x 0.004 inches |
| Special Feature | Long,Strong |
| Surface Recommendation | Plastic |
| UPC | 638060401323 |
| Unit Count | 1.0 Count |
| Water Resistance Level | Waterproof |

## Product Details

- **Brand:** 3M
- **Color:** Silver
- **Material:** Acrylic
- **Number of Items:** 1
- **Recommended Uses For Product:** Sealing

## Images

![3M Aluminum Foil Tape 3340, 2.5" x 50 yd, 4.0 mil, Silver, HVAC, Sealing and Patching Hot and Cold Air Ducts, Fiberglass Duct Board, Insulation, Metal Repair - Image 1](https://m.media-amazon.com/images/I/91kKcruIt5L.jpg)

## Available Options

This product comes in different **Pattern, Color** options.

## Customer Reviews

### ⭐⭐⭐⭐⭐ Genuine 3M Quality
*by S***. on March 11, 2026*

Genuine 3M product, Quality as expected, Easy to cut to the correct size before placing it, with the backer paper protecting the sticky side, but sticks were you put it. I used this to patch some gaps in aluminum ductwork directly below the furnace output, and it has stayed stuck through both Heating and Cooling cycles.

### ⭐⭐⭐⭐⭐ The high quality aluminum “duct” tape
*by P***N on August 23, 2023*

This is the good one, this stuff is tough too. I always like to have some on hand for projects around the house. You’d be surprised how useful this tape can be once you have some on hand. My dad always used this at work (HVAC) so I’ve learned over the years how to properly use this tape to make my A/C more efficient. This is great for taping up cracks around your furnace or condenser coil. You can also use it to tape the chill line near the outside unit if your lines have areas that are exposed, or if there are places that are beginning to be exposed. You can buy cheaper brands, but there’s some things you shouldn’t buy off brand, and this one of them. Buy the legit 3M tape, it’s worth it. It’ll save you money in the long run as you won’t constantly be having to patch up previous applications. I’m not a certified HVAC tech, but after riding with my dad from elementary school until I graduated, I do know to highly recommend this specific tape. This can also be used on small windows, such as the small window panes on some front/back doors, and for lots of other applications. If you’re a homeowner, I truly believe a roll of this tape should be in your home tool box.

### ⭐⭐⭐⭐⭐ Great stuff
*by D***N on February 28, 2026*

Great stuff. Sticks very well

## Frequently Bought Together

- 3M Aluminum Foil Tape 3340, 2.5" x 50 yd, 4.0 mil, Silver, HVAC, Sealing and Patching Hot and Cold Air Ducts, Fiberglass Duct Board, Insulation, Metal Repair
- Red Devil 0841DX F-Seal 181 Duct Seal, Fiber Reinforced Water Based Duct Sealant, 1 Gallon, Gray, Made in USA
- 3M Venture Tape UL181A-P Aluminum Foil Tape 1581A, Rigid and Flexible Duct Seaming, Durable, Cold Weather Adhesion, 3.89 in x 60 yd, 2 mil

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*Product available on Desertcart United States of America*
*Store origin: US*
*Last updated: 2026-03-21*