The giottos mh 646 quick release plate is the replacement plate for the mh 656 quick release system and in addition since this plate features the arca type mount it is also compatible with any of the many other brands that use this standard eg arca swiss foba grafstudioball wimberley etc it will not fit the arca swiss flip lock anti twist reversible tabs on the plate can be used to prevent slippage when using the head in a vertical position a finely machined plate for arca ty