Length: 1 Roll of 50 Feet. Standards: AMS-DTL-23053/5. Size: 3/8 Inch. . . FIT heat-shrink tubing offers a reliable way to protect and seal terminations or add additional mechanical ruggedness. FIT preferred heatshrink products are made from premium compounds under the tightest manufacturing controls. This means FIT will consistently have excellent physical characteristics such as low longitudinal shrinkage and wide temperature ranges while providing an elegant appearance when used alone or on OEM equipment.. Alpha Wire. Alpha Wire. FIT-221-3/8 BK007. UPC: 013227166060. EAN: 0013227166060. GTIN: 00013227166060.