The Grab differential Limit Switch is Driven by holding & closing winches & used auxiliary circuits for single lever grap control. It is used for stopping the closing motor after closing or opening, regardless of the height of the grab and starting the holding motor after closing, or apening, regardless of the height of the grab and starting the holding motor after closing, for transition to the hoistion actions as well as for stopping the holding & closing motors at the hoisting and lowest grab position