General
Degree of protection	Medium-walled
Material	Polyolefin (PO-X)
Internal coating	with adhesive
Operation temperature	-55 to +110 °C
Storage temperature	-10 to +40 °C
Storage humidity	<75 %
Durability	24 months
Minimum temperature for shrinking	+120 °C
Longitudinal shrinkage	0 ±10 %
Shrink ratio	3,5:1
UV resistance
Halogen free
Printable

The RED heat shrink tube type SMK 40.0-12.0 is a medium-wall heat shrink tube with an internal adhesive, supplied in 1-metre lengths. It is used for mechanical and electrical protection insulation of cables, wires, and electrical connections, particularly in low-voltage applications. Due to its UV resistance and halogen-free composition, it is suitable for outdoor use as well as in environments where the avoidance of toxic fumes during heat development is required.

Applications
The heat shrink tube is used in electrical and IT installations to protect cables and wires against mechanical stress, moisture, dust, and UV radiation. It is particularly suitable for applications outdoors, in industrial environments, for mounting plug connections, or for labelling cables by printing. The halogen-free formulation also makes it suitable for applications in buildings with increased fire safety requirements.

Functions and Features in Detail
The heat shrink tube is made of polyolefins (PO-X) and has a medium-wall construction, ensuring sufficient mechanical strength and simultaneous flexibility. The inner surface is coated with an adhesive that melts when heated, creating a tight, form-stable bond between the tube and the underlying cable or conductor. The surface is printable, allowing labels to be directly applied to the tube, which facilitates identification of wires during operation.

Technology Explained Simply
When heated to at least +120 °C, the tube shrinks to approximately 30 % of its original diameter (shrink ratio 3.5:1), with maximum longitudinal shrinkage of 10 %. The shrinkage occurs evenly, resulting in a tight fit. The internal adhesive ensures that the tube adheres firmly to the cable after cooling, preventing any gaps or air pockets. The operating temperature range is between -55 °C and +110 °C, enabling use in various climatic environments. Storage should be at temperatures from -10 °C to +40 °C and relative humidity below 75 %. Shelf life is 24 months from date of manufacture.

Compatibility and Accessories
The heat shrink tube is designed for use with cables and wires in low-voltage applications. As suitable accessories, the heat shrink tube MA47-40/12-1000-BK (black, 3.5:1) is offered, which is also suitable for similar applications. The use of heating devices such as heat shrink guns or hot air blowers is required to initiate shrinkage. Shrinking with an open flame is not permitted due to fire hazard.

Installation and Mounting
Installation is carried out by sliding the tube over the cable or connection to be protected, followed by heating with an appropriate heating device. The temperature must reach at least +120 °C to ensure complete shrinkage. After cooling, the tube adheres firmly to the cable, creating a tight, watertight, and mechanically stable insulation. The maximum longitudinal shrinkage of 10 % must be considered during planning of the tube length to ensure sufficient overlap.

Operational Advantages
The heat shrink tube provides a reliable, durable protective layer that protects against environmental influences such as moisture, dust, UV radiation, and mechanical stress. The halogen-free composition reduces fire hazard and the formation of toxic gases when heated. The printable surface allows for clear labelling that remains legible even after prolonged operation. The medium-wall construction offers a good compromise between strength and flexibility, facilitating processing and use in various installation scenarios.