Rated for UL VW-1 flammability test specified by UL 224 standard, DWFR (dual wall, fire-retardant) heat shrink tubing comes in 14 sizes from 3–52 mm ID and is applicable to range of electrical connections and terminations. Flame-retardant polyolefin jacket and thermoplastic inner adhesive wall provide electrical insulation and mechanical protection. When properly installed, tubing shrinks to create moisture-resistant seal. Heat shrink ratios of 3:1 and 4:1 enable diverse use.