The 202D921-100-0 from TE Connectivity / Raychem Brand is black color heat shrink boot with shell size 21. This heat shrink boot has 0.760" (19.30mm) to 0.512" (13.00mm) large diameter and 0.177" (4.50mm) to 0.083" (2.11mm) small diameter. This is polyolefin (PO), semi-flexible, halogen free, irradiated heat shrink boot with length of 2.370" (60.20mm). Operating temperature range is from -30 to 105 °C (-22 to 221 °F).