The stock balance point on the X-10 is neutral, the radio hangs fairly level. Many people prefer their transmitters to hang with a slight tilt, top of the transmitter pointed toward the ground. This slight angle better matches the natural angle of the wrist making the transmitter more comfortable to hold.
Installation is pretty straight forward. Insert the vinyl tubing spacer into the neck strap mount on the X-10; push the balance bar into position and thread in the screw from the left hand side. When the threads emerge on the other side position the nut so it fits into the machined recess in the balance bar; tighten.