2 used washing line stretchers. Metal. Grey.
About 7’ long as seen.
I can’t unscrew them to telescope them or extend or shorten them. They seem stuck. But maybe someone stronger could do it. Or a couple of pairs of pliers.
One currently slightly longer than the other.
Could be right height for your line. They were for mine until I changed to a retractable line which is mounted higher up than the poles.