Is the effective length of the device length is 4000, as well as in front of the cylindrical head, there is a length of the head, so that, the enough length
The length of the device is the effective length is 4000, the front has a cylindrical head, the head also has a length, so that this length is sufficient
The effective length of the equipment is 4000. There is a cylinder head in front of it, and there is a piece of length in the head. So, this length is enough.<br>