Abstract: A plug for sealing holes, particularly in aircraft fuel tanks, having an elastomeric tapered body member of circular or rectangular cross-section, formed of a plurality of integral tapered portions of successively reduced taper extending substantially from one end to the other end of the body member, each tapered portion having an exposed outer edge, providing a tapered and barbed configuration. A lead-in tip is provided at the tapered end of the body member. In use, the plug is inserted into and pulled through a hole to be plugged and into tight contact with the inner surfaces and edges of the hole. When the tensile pull is relaxed, this allows the plug to expand into contact with and grip the inside hole surfaces and hole edges, to form a positive seal. Excess plug material is trimmed off on one or both sides of the hole, and a coating of sealant material can be applied on the outer surfaces of the trimmed plug at opposite sides of the hole for additional sealing.