King is the major producer of manufactured ceramic waterstones in Japan and for good reason – they produce the best low-cost manufactured stones in the country and generally regarded as the industry-standard waterstone, not only in Japan but also Australia.
The 300grit stone can be used for reshaping tools and/or for use on coarse steels like gardening tools etc. The 800grit stone is for repairing major nicks in your woodworking blades and chisels or for your general household sharpening. The 1200grit stones are perfect for giving your tools a quick touch-up if you sharpen regularly before moving on to your finer grit stones.
These stones should be stored in water when not being used.