DMT - USA MADE
Diamond plates excel at the process of flattening other types of sharpening 'stone' including waterstones and ceramics and hand plane bases among numerous other dressing needs .
To do this put a cross hatch of ink from a felt tipped pen on the item to be dressed and work the device evenly over the plate. Water is the best lubricant. It will be clear in an instant how flat the device is.