Got this from Team Orion.
Blue - 5mm armature web, enduro brushes, off-road winds
Black - 4mm armature web, enduro brushes, touring winds
Green - 4 mm armature web, sprint brushes, off-road winds
Purple - 4mm armature web, Sprint brushes, touring winds
The Blue V2 is the weakest of all but is more economical. Lasts longer in between rebuilds.