Heat Shrink Thin Wall Flexible Polyolefin Tubing 600V Color: null Shrink Ratio: 2:1 Size: 1/2 Expanded Insulation Diameter: 0.500 Recovered Insulation Diameter: 0.250 Tube Length: 100 Reel. Provides: null Moisture and Abrasion Protection in Stain Relief and Wire Bundling Applications. 3M Heat Shrink Tubing FP-301 offers an outstanding balance of electrical physical and chemical properties for a variety of industrial and military applications. FP-301 tubing is split resistant mechanically tough easily marked and resists cold flow.