My Gitzo GH1780 ball head. Modified by addition of a Hejnar Photo arca swiss clamp head. Properly compatible with arca swiss plates and L-brackets.
Please note I do not have the original Gitzo clamp.
This functions perfectly, the Hejnar clamp is solid and dependable and fully compatible with arca swiss type plates and L-brackets.
Only selling because I have sold the travel tripod to which it was attached and am unlikely to replace it.