Heat Shrink Tubing Heavy Wall Material Cross-Linked Polyolefin with Adhesive Flame Retardant No Adhesive Lined Yes Shrink Ratio 3 1 Use With Wire Size 250 MCM to 600 MCM I.D. Before Shrinking 2 in I.D. After Shrinking 0.63 in Wall Thickness After Shrinking 0.16 in Length 4 ft Shrink Tubing Properties High Heat Resistant Color Black Temp Range -67 Degrees to 230 Degrees F Package Style Individual Pieces Min Shrink Temp 248 Degrees F Dielectric Strength 600 V