The Shimano tool is superior: the ring around the edge helps to correctly position the prongs on the freewheel body. Once you secure the tool to the wheel with the axle nut or quick release skewer, the Shimano tool is less likely to disengage from the freewheel body than the traditional two prong, unsupported tools. The Regina two prong freewheels are _very_ prone to damage when the tool slips or metal fatigue causes the body bosses to deteriorate during removal.