Generally called pilot valve. It is used to distribute the pilot oil circuit, and there are two solenoid valves above, one is used to control the rotary action of the excavator, and the other is used to cut off the pilot oil circuit (that is, the safety valve).
There is a cylinder on the pilot valve group, which is filled with nitrogen called accumulator, which is used to drop the working device by its own weight after the engine is turned off (the hydraulic oil in the valve group is under certain pressure after the engine is turned off, which can push the valve stem of the main control valve to make the oil circuit of the working device open). The last remaining part is the fuel supply to the pilot control handle.