Abstract: An externally expandable earless clamp structure, in which a hook-like member in the outer band portion is adapted to engage in a hook-receiving aperture in the end area of the inner band portion to connect the overlapping band portions, a first inwardly pressed-out tool-engaging embossment in the inner band portion is adapted to cooperate with a second inwardly pressed-out tool-engaging embossment in the outer band portion to permit tightening of the clap structure by expansion thereof; and an inwardly pressed-out tab-like member in the outer band portion extending in the longitudinal direction is adapted to engage in a narrow slot in the inner band portion.