Brady bmp21 series permasleeve wire marking sleeves, 3-8 dia x 7’l, black-white, m21-375-c-342 the b-342 polyolefin permasleeve material is a non-adhesive, heat-shrinking sleeve that fits around wires or cables for easy permanent identification. 3:1 heat-shrinking wire sleeve is ideal for labeling in harsh environments and is resistant to chemicals, grease, oil and cleaning agents. Polyolefin wire marking sleeves have a smudge-proof finish and print in black text on a white background. Permasleeve labels provide wire identification that combines speed, ease of use and permanence for long-lasting, high quality identification. Cold resistant and flame-retardant with an operating temperature of -67f to 275 f -55 c to 135c. Permasleeve wire labels are ideal for electrical contractors, maintenance crews and industrial professionals.