Abstract: An expansion plug has a pair of expansion shanks separated by a slit which extends along most of the length of the plug. A receiving channel for a fastener extends within the plug and along its length. The outer surface of each shank has a plurality of teeth which do not extend beyond the cylindrical profile of the plug. A pair of locking tongues extends outwardly from the plug at an acute angle to the plug axis. The expansion shanks are connected to each other by a series of longitudinally extending and longitudinally offset frangible wall portions.