This is a grapnel rocket launch kit for use with World War II vintage U.S. Navy rockets for throwing lines. The kit was developed by the American inventor Wadsworth W. Mount for the purpose of throwing life lines for rescue work at sea, or from ship to shore as life saving rockets. They were also to be used to climb cliffs and for breaching beach defenses. Standard U.S. Navy 1.25-in.and 3.25-in. rockets provided propulsion.

Successful tests of these rockets were conducted from 1944 to 1946 at Fort Belvoir, Virginia, and elsewhere. However, Mount's rockets were not adopted by the Coast Guard or other services, although they were allegedly adapted for testing soil samples during post-war Atomic bomb tests. Mount donated the kit to the Smithsonian by in 1976.