The advantages of a Two-Rope Grab or Four-Rope Grab on respectively Two Line (one holding and one closing) or Four Line (two holding and two closing) operated cranes, are: (1) control of the mechanism is simple and dependant on crane speed, (2) possibility of false engagement of the mechanism is practically excluded, (3) possibility to close or open the grab in full crane speed without previous stopping, (4) optimum balance between dead weight and crane capacity provides maximum efficiency with low maintenance effort.