FP-301 heat shrink tubing has a 2:1 shrink ratio. When heated, the tubing will shrink up to to 50 percent of its original internal diameter. The wall thickness of the tubing after shrinking is proportional to the degree the tubing was shrunken. Minimum shrink temperature for FP-301 tubing is 212Â°F or 100Â°C. FP-301 heat shrink tubing is ideal for fire-resistant coverings of components and flammable wire assemblies. FP-301 tubing is rated for continuous operation at -55Â°C (-67Â°F) to 135Â°C (275Â°F), and is designed to withstand elevated temperatures to 300Â°C (572Â°F) for short periods. Minimum shrink temperature for all FP-301 tubing is 100Â°C (212Â°F).