Is this compatable with the Arca Swiss camera plates ?
NO!!!!!!!!!!!!!! Beware!!!!! I bought this item hoping it would really be an "Arca-Swiss compatible" head but it is only "compatible" if you use the plate that came with it!!! The plate will work on other Arca-Swiss heads, but other Arca-Swiss plates won't work on this MSQ6! To be honest, I quit with Manfrotto. Too funky. Too many times I've heard from photo shop clerks and reps that Manfrotto is often incompatible with other brands a/o has different specs from industry standards. This MSQ6 is a good example.
The issue with the MQ6 is that there is a little retractable "catch clip" (or whatever it's called) that hooks over the bottom "rail" of the Arca-Swiss plate. The special Manfrotto plate that comes with this head has an especially thin "rail", so the catch clip is just able to reach over the rail and come down on it to lock it in when you tighten the screw. Most other Arca-Swiss plates have thicker rails so the catch clip cannot clear the rail and so can't lock the plate. (This explains why, on the other hand, the Manfrotto plate can work on other Arca-Swiss heads.)
I got frustrated with the Manfrotto head and now have a Gitzo head that much more easily accepts a variety of other manufacturers' Arca-Swiss adapter heads and will take any brand of Arca-Swiss plate. For the money you'd spend on this adapter, I'd put it towards a Gitzo head (such as Gitzo GH1780 Series 1 Magnesium Center Ball Head, (Load Capacity 22.05 lbs.)) It's a much better head, lightweight, one-touch adjustment, and more versatile for adapters. Oh, and other manufacturers' adapters for Monfrotto tend to be more expensive because they have to be "special made" to fit the quirky Manfrotto specs.
Hope this helps!