In my googling I came across a Chinese company called Konbo international. http://www.konbo.com/en/ I don’t know anything about them and details are hard to come by. Nobody seems to stock their stuff and I mostly found references to them at trade shows etc. After a while I found some of their yoyos on ebay. Twelve bucks for a metal yo seemed worth a look. After a couple of weeks wait for it to arrive from Hong-Kong, it arrived today.
The Koyo Stainless Steel Butterfly
See pics here: http://gallery.me.com/pavig#100033
The yoyo is structured kind of like two steel bowls (see pics) held together by outside bolts on the axle. Mine has a blue baked on powder coating, though you can get them in brushed or polished steel too. On each side inside there’s a plastic response pad (starburst). custom metal shims hold the small bearing in place. It came with a full cotton string.
It’s heavy! 75 grams they say, and it feels solid as a rock on the string. With all that weight it sleeps for a looooong time. The gap is about the same as a wound in speedmaker. As for size it seems exactly the same width and diameter as my protostar. With all that momentum it’s very easy to land on the string.
It plays well. With the starburst it is responsive, but not overly so. It won’t return unless you ask it. With the comparatively narrow gap you can’t wind a lot of string into it before you get friction, but it’s not too bad. The recess in the starburst pad is large enough to accommodate a large bearing if you could figure out how to lock it to the thin axle. After disassembly it needs a bit of tuning to get rid of vibe, but then spins very clean.
So there it is - the Koyo metal. Cheap, heavy, strange, a reasonable player with possible modding potential.