All chokes are different, and most hunters focus on the exit diameter only. The internals of a choke and the wad stripping abilities (taper of the internal opening) can vary (think thousandths) which will impact pellet and pattern performance (375+) with TSS #9s. Generally speaking TSS, does not have to be choked like lead (Longbeard shells), thus I would be suspect of the choke in general. The only way to know for sure is to buy it and shoot it. With so many mail ordering stuff these days, and the possibility of a return, I'd stick with the tried and true chokes that others have used with TSS #9s for the last decade. Furthermore, I've read hundreds of posts on 3-4 forums about choke recommendations for Remington 870 20G TSS #9s, and I've never seen a Longbeard choke tested or recommended.