• DHST: Product Type (Dual-wall Heat Shrink Tubing)
• 3X: Shrink Ratio (3:1)
• 12.7: Nominal Inner Diameter Before Shrinking (12.7 mm)
• BLK: Color (Black)

• MHST: Product Type (Medium-wall Heat Shrink Tubing)
• A: Adhesive-lined (Contains internal sealant)
• 95/25: Inner Diameter before / after shrinking (95 mm / 25 mm)
• BLK: Color (Black)

Heat shrink tubing has different shrink ratios, like 2:1, 3:1, 4:1 and 6:1. These ratios indicate how much the tubing can shrink in diameter. For example, a 2:1 shrink ratio means the tubing can recover to approximately half of its original inner diameter.

So firstly, you need to measure the diameter of the biggest part and the smallest part of your object to cover. For example, if the largest part of your object is 11mm and the smallest part is 5mm, a 3:1 shrink ratio tube with a 12.7mm initial inner diameter may be suitable. Always check that the fully recovered inner diameter is small enough to provide a secure fit.

Then, how do I choose the right size if my object is not round?

1. Measure Perimeter: Measure the total perimeter of your object.
2. Calculate Diameter: Divide the perimeter by 3.14 (π). The result is your equivalent diameter.
3. Select Size: Choose the tubing size closest to this calculated value. Note: For a tight fit, ensure the tubing’s fully recovered inner diameter (the smallest diameter after shrinking) is smaller than the largest dimension of your object (e.g., the diagonal for a square object).

When selecting heat shrink tubing, consider the following key specifications:

• Initial Inner Diameter: The internal diameter of the tubing before shrinking.
• Fully Recovered Inner Diameter: The internal diameter after the tubing has been fully shrunk.
• Wall Thickness: The wall thickness before and after full recovery, as specified in the product datasheet.
• Shrink Ratio: The ratio between the original and fully recovered inner diameters, commonly 2:1, 3:1, 4:1 or 6:1.
• Adhesive Lining: Single-wall tubing has no internal adhesive, while dual-wall tubing contains an adhesive lining for additional sealing.
• Minimum Shrink Temperature: The temperature at which the tubing begins to shrink.
• Operating Temperature: The temperature range within which the tubing is designed to operate continuously.

Inner Diameter: The internal diameter of the tubing when it is in its round, open shape.

Flat Width: The width of the tubing when it is flattened.

Formula:

Flat Width = Inner Diameter × π ÷ 2

Heat shrink tubing may also shrink slightly in length during installation. This is known as longitudinal shrinkage and is typically less than 10%, depending on the product. We recommend allowing some extra length when cutting the tubing to ensure sufficient coverage after shrinking.

Polyolefin is one of the most widely used materials for heat shrink tubing due to its flexibility, electrical insulation properties, and versatility.

Other materials include PTFE (Polytetrafluoroethylene), FEP (Fluorinated Ethylene Propylene), PVDF (Polyvinylidene Fluoride), elastomers, silicone rubber, and fluoropolymer materials such as FKM.

PVC heat shrink tubing is also available in the market and is generally a lower-cost option. Its flame-retardant performance depends on the specific formulation.

Certification and compliance vary by product and material. Selected products meet relevant UL requirements and RoHS or REACH compliance requirements. Please refer to the individual product specifications or contact our sales team if you require specific compliance documents.

Flame-retardant heat shrink tubing is designed to help reduce the risk of flame propagation in electrical and industrial applications.

Many of our heat shrink tubing products offer flame-retardant properties and selected models meet the UL 224 VW-1 flammability requirements. Please check the individual product specifications for applicable ratings.

A heat gun is the most common tool used to install heat shrink tubing. For production environments, a controlled heating oven may also be used to provide consistent and uniform shrinking.

For large-diameter or heavy-wall heat shrink products, suitable industrial heating equipment or a controlled gas torch may be required. Always follow the product’s recommended shrinking temperature and installation instructions.

No. Once heat shrink tubing has been fully recovered, it cannot return to its original expanded size. Make sure you select the correct size and position the tubing properly before applying heat.