This thing is a clamp that fits on your Ego powerload string trimmer carbon fiber shaft... or any brand trimmer shaft with a diameter of 25mm. It has a metal rod that serves as the clamshell hinge to allow easy installation and removal as well as providing a point on which to snap on your existing shoulder strap buckle. I know, you could always buy the official Ego one (the cheapskates really should have included it!) but what fun would that be? And besides, you likely already have a strap around the house. And this one will be easier on the carbon fiber shaft than the metal clamp end on the Ego piece. Check back here later to see if my TPU version is strong enough. I believe it will be since there are no thin parts that will be overly flexible. Or you can try that yourself.

Edit: I just made a small change to rotate the hex indent to capture the nuts better.