What is this hydraulic thingy

[oldnslo]

Although I agree orientation of restrictor disk is important as to which direction oil is restricted. I see no way the disk can wedge in a port or hose because the disk has a larger diameter than hose & valve port is machined to limit disk penetration. On many applications restrictor disk is fitted between hyd coupler/tip and hose

Not wedging is true IF the port is made to a size per a standard. I have seen where the predrill diameter on the port was the same as the minor diameter of the threads. These discs won't work then.