Heat Shrink Thin-Wall Flexible Polyolefin Tubing 600V Color: null Shrink Ratio: 2:1 Size: 1/16 Expanded Insulation Diameter: 0.063 Recovered Insulation Diameter: 0.031 Tube Length: 100. Provides: null Moisture and Abrasion Protection in Stain Relief and Wire Bundling Applications. 3M Heat Shrink Tubing FP-301 is a general purpose thin wall tubing that provides a balance of electrical physical and chemical properties making it ideal for industrial and military applications. This tubing has a 2:1 shrink ratio and provides flame retardant insulation for 600V rated applications. It has a flexible polyolefin construction that offers moisture seal protection.