FIT® 221 is the most widely used general purpose heat-shrinkable tubing. It is flexible, flame-retardant, self-extinguishing and fungus-resistant. The tubing shrinks a minimum of 50% of supplied diameter at 121°C with longitudinal shrinkage at 5% (UL224). Operating Temperature: –55°C to 135°C. Tensile Strength: 1500 psi.