Ancor 3/4 x 48 Black heat shrink tubing. Insulates and protects connections from mechanical abuse, wire pullout and abrasion. Heat activated adhesive lining provides impervious seal to salt water, oil, acids, and sunlight as well as providing strain relief. Highest shrink ratio - shrinks to 1/3 original size. Shrinks at 257 deg F/125 deg C.