A plug element for conducting tests of a well, a pipe or the like, comprising one or more plug bodies of disintegratable/crushable material set up to be ruptured by internally applied effects, is disclosed. The plug element of the invention comprises an internal hollow space set up to fluid communicate with an external pressure providing body, and the plug is designed to be blown apart by the supply of a fluid to the internal hollow space so that the pressure in the hollow space exceeds an external pressure to a level at which the plug is blown apart.