What is this?

Hiya!

I just bought this set from a chinese set as I want to get into gong fu brewing. It is not precisely what I wanted, as I was looking for a porcelain set with a gaiwan, but this will do.

However, I cant quite work out what the piece pictured separetely is. I already have a filter with a sieve for the fairness cup (or at least thats what I think it is).

Does anybody know what that piece is supposed to be?

Thanks!