FUNimation has announced set release dates for Dragon Ball “Z” Kai, Dragon Ball Season Four and Dragon Box Volume Three (all releasing May 2010).

Dragon Ball Z Kai : 05/18/2010
Dragon Box Volume Three : 05/04/2010
Dragon Ball Season Four : 05/04/2010

You can pre-order the Dragon Box Volume 3 (DVD), Dragon Ball Z Kai (DVD | Blu-ray) and Dragon Ball Season Four (DVD) all from Right Stuff.

Sources : Rightstuff and Toon News