Duct tape, originally called duck tape, is a strong, fabric-based, self-adhesive tape with a number of variants, and an extremely wide range of applications. The most common form has a silvery gray side without adhesive and an off-white adhesive side; this, and the range of uses, has led to irreverent comparisons with the Force in Star Wars: it has a light side, a dark side, and holds the universe together. The actual tape has three layers: a top polyethylene layer, fabric and adhesive. At least 20 colors are commercially available.
Developed as a general-purpose mending tape for the U.S. military in World War II, the original version, made by the Permacel division of Johnson and Johnson, was branded "Permacel", and derived from a medical bandaging tape. Its fabric base allowed it to be ripped easily to the needed size. It made use of a new class of adhesives, Polycoat. "The resulting tape was nicknamed "Duck Tape" for its ability to repel water, while ripping easily into strips for fast convenient use." The military version was olive green as opposed to today's gray.
It has been replaced, for applications with heating and cooling ductwork, by self-adhesive metal tape or liquid sealants. 1998 work at Lawrence Berkeley Laboratory found it has a short service life in this application.  but the most common name remains duct tape.
In photography, a similar, deliberately thinner, more flexible, and not as strong, variant is called "gaffer's tape." Today, a green version is apt to be military, and much stronger than the commercial version. The latter, for example, is used for temporary repair of holes in the outside skin of combat helicopters. "EB Green", presumably from the Electric Boat shipyard, is an extra-strong version used for repairs on U.S. Navy submarines.
"Thirty years later, Jack Kahl, former CEO of Manco, Inc., changed the name of the product to Duck Tape® and put ‘Manco T. Duck’ on the Duck Tape® logo, giving personality to a commodity product. Manco, Inc. also began to shrink-wrap and label the product, making it easier to stack for retailers, and easier to distinguish different grades for customers.