Amazon has the Gardner Bender 10-Foot Self-Sealing Silicone Repair Tape (Black, HTP-1010) for $8.23 with free shipping on $25+ or with Prime. Features 1" x 10' roll, self-bonding, air & watertight seal. The tape insulates split bolts, y-splices, and outdoor electrical installations. It temporarily repairs auto radiator hoses, garden hoses, and water pipes, plus it provides non-slip grips on sporting goods and other surfaces.
Has good Amazon Reviews.