Duct tape

Strongly adhesive, waterproof cloth tape, usually coated on the cloth side with a thermoplastic such as polyethylene. Most often used for sealing ducts against moisture and air leaks, but also used for more general purposes. The 3-ply product was initially composed of a plastic cellulose nitrate laminated cotton strips coated with a rubber-based adhesive. Within a short time, the plastic coating was switched to polyethylene to increase water resistance.