Ami Ami, who have begun accepting preorders.
Volume 2 once again features nine classic series characters, though only seven have been revealed. While volume 1 was primarily focused on protagonists, volume 2 looks to be themed after Rockman 1 Robot Masters, save for the inclusion of a lone Rockman strap.
As with volume 1, you won't know what straps you'll get upon purchase; they're pretty much trading figures. Ami Ami is selling them in boxes of eight, so there's a chance you may wipe out most of the collection in one fell swoop... or end up with a bunch of duplicates. You never know!
Dot Strap collection volume 2 is set to ship in mid-July for 3,100 ($36.47 US). Preorder your set here.
Thanks for the tip, Heidi!