Fiberglass tape is typically a narrow cloth strip made of twisted strands of fiberglass that are woven at right angles to one another, with woven edges to prevent unraveling. It comes in varying types (e.g., woven, biaxial), weights (e.g., 4 oz., 6 oz.) and widths. For boat building and repairs, this type of fiberglass tape is used to reinforce seams and corners, and is placed over epoxy fillets on plywood stitch-and-glue boats.
The fiberglass cloth tape we carry at Jamestown Distributors (shown above) is for boat building and repairs, and does not have an adhesive backing.
Typical self-adhesive fiberglass tapes available at the big box stores are used for drywall joints. They're stiff, have a weak grid of fiberglass, and do not conform to curves and corners. These self-adhesive fiberglass tapes are not recommended for boat building and repairs.