The present disclosure provides for a reversible and adjustable stopper assembly comprised of an upper frame, L-bracket, connector portion and stopping member. The stopper can be configured to be secured to at least two main types of press brakes. The stopping portion of the stopper is also reversible, allowing for less sheet metal to be inserted into the press brake, if desired. The stopper assembly can be slid in a horizontal manner, relative to the press brake to preserve the measurement of the sheet metal from one end of the press brake to the other.