Promaster's my harp!
I bought some with valves, but ended up pulling the valves out. They rattle. I do like what the do, though, but ... that darned rattling!
There are harps with better valves, but I don't know which ones they are. You can also buy valves, but that darned Super Glue can cause problems when applying. That stuff can easily run to where it shouldn't, and freezr reeds. Oh, you can peel it off... I've done it, but I don't wanna do it again!