MKV Stedi-Cam Garfield Mount
The MK-V Garfield mount is a very sturdy hard mount with various options for mounting. Usually used on Dolly's, Quad bikes, tracking vehicles, etc. This is what you need to rig your stedicam to Mitchell or speedrail.
It has an industry-standard socket block on for mount (Also available without) and can be rigged either left or right-hand side.