Raychem ATUM Tubing 4:1

Raychem ATUM 4:1 Heat Shrink Tubing — Military-Grade Adhesive-Lined Motorsport Sleeving

Raychem ATUM 4:1 is the industry benchmark adhesive-lined cross-linked polyolefin heat shrink tubing for motorsport, aerospace, and military wiring applications. With a 4:1 shrink ratio, ATUM accommodates a much wider range of pre-shrink to post-shrink diameters than standard 2:1 or 3:1 products, making it exceptionally versatile for connector strain relief, splice protection, and environmental sealing over irregular-geometry harness features such as multi-wire breakout points and connector backshell entries.

Why Raychem ATUM Is the Professional Motorsport Standard

Raychem (TE Connectivity) developed the ATUM specification for military and aerospace wiring where environmental sealing and long-term reliability are non-negotiable. In motorsport harness building, ATUM has become the de-facto premium choice at high-specification connector backshell entries, over breakout sleeves at harness branch points, and at any location where a high shrink ratio is needed to conform tightly over a large-diameter change in the harness cross-section. The cross-linked polyolefin outer wall withstands temperatures up to 135°C continuous, and the hot-melt adhesive inner lining provides reliable sealing even over rough or uneven surfaces.

4:1 Shrink Ratio — Application Advantage

The 4:1 shrink ratio means ATUM can be slid over a large pre-shrink diameter and then shrunk to form a tight seal over a much smaller finished diameter. This is particularly valuable at connector backshell entries where the overall connector body diameter significantly exceeds the exiting cable bundle diameter, and at harness branch points where the bundle splits into multiple smaller sub-looms. Standard 2:1 tubing does not accommodate this diameter change effectively.

Available from Arctic Performance Parts

Raychem ATUM 4:1 tubing is available in a range of diameters to suit all common motorsport harness applications. Arctic Performance Parts stocks ATUM tubing alongside the full range of motorsport heat shrink products to support professional harness builders across Norway, Sweden, and Denmark.