This arrived today. I'm collecting parts for my 1983 Fisher Montare (urban mountain bike for clandestine alley racing), I was looking for a frame mount bottle opener for the third bottle mount. I discovered through a secret source that STARR "X" bottle openers have a compatible bolt pattern for standard bottle cage mounts. I verified the fit and 4 ea. 5 mm washers are required for a rock solid installation due to the slightly oversize countersunk holes, so yes its a complete bolt on. There are hundreds of these bottle openers on Ebay starting at $10.00, so quite a bargin compaired to the billit wonders out there.
: Mike