Abstract: An outer mounting body is made of semi-soft material having a primarily flat planar shape formed with an upper housing portion, and an outer flange portion having a planar upper surface tapering from the housing portion to outer peripheral edges of the mounting body and adapted to be mounted to flexible or curved surfaces such as those of an inflatable surfboard. An inner mounting insert made of rigid material is molded within the outer mounting body and has an upper recess for sturdily mounting an object such as a surfboard fin. The inner mounting insert may be formed asymmetric for reversibly mounting left and right side fins near the edges of a surfboard.