The Shapton GlassStone HR Series of Ceramic Waterstones is Shapton’s most advanced series of stones for sharpening hard steels and modern steel alloys. They are one of the highest quality stones available at any price. Manufactured to the strictest tolerances, the Shapton GlassStone is a high quality ceramic waterstone that uses uniform ceramic abrasives to provide a consistent and fast cut. The stones are backed with glass (hence the name GlassStone) to provide an exceptionally flat base. The Shapton GlassStones measure 8 1/4″ long and 2 3/4″ wide x 3/8″ thick (210mm x 70mm x 10.5mm). Made in Japan.