Hard rubber; hardness is 63; best to use in tropical countries and soft rubber; hardness is 53; best to use in frigid countries and best result on window cleaning but lifetime is shorter than hard rubber.                                             The Ergo version has a streamline design to fit better the hand grips of operators. It is also lighter in weight, more comfort in works and carrying. In case of dropping on ground, chance of deforming the channel or the handle opening is less likely. The last but not least is that, it is more environmental friendly in production process. No buff polishing is necessary which is a very polluting and health hazardous process.          
The secret of the window squeegee is the rubber blade; the cutting edge of the blade; with sharp edge and carry away dirt and no residue remain with only a single slide on the glass.