You mean a neck strap? A strap or sling sold for clarinets may have a leather tab to attach to a typical thumb rest, because a typical T rest does NOT have a ring. Yours HAS a ring for a strap hook (common on Chinese clarinets). It probably gets in the way of the tab. So, you want to buy a SAX strap - one with a simple hook, that will go through your ring. A cheap one with string is good, because you may have to shorten the string, and it's easy to do.
You can also make one easily - just copy a typical cheap sax strap. I use a strap now because I strained my R thumb.