The Sigma Power company has produced a ceramic whetstone that cuts rapidly and gets the job done. Like all good whetstones these are not cheap, and must be considered an investment that is made to ensure one can sharpen your own straight razors, knifes and other tools to a superb level of sharpness for decades to come.
The lower grit stones are generally hard, and yet still cut aggressively so your work is done quickly. They are highly resistant to dishing, but do require a short soak of 5 minutes prior to use. Keep the stone wet while in use by having water in a spray bottle on hand all of the time.
Sigma also claims a stone that is stronger than other brands on account of their composition and manufacturing processes, and we also love the fact that it is twice as thick as most other stones on the market. The 25 mm thickness means you'd get more than double the amount of work out of it when compared with most other makers who supply their stones in a 10 or 15 mm thickness.
This #400 stone is for rough sanding, it is ideal for dressing and truing, fixing nicked edges or taking off lots of stock when correcting the geometry of the blade itself.
When an tool or knife's edge geometry needs correcting, the #1000 stone will restore it quickly, effectively and with minimal dishing.
To refine the edge, the Sigma Power #6000 gets the job done with a minimum of fuss, and leaves the edge sharp enough for everyday tasks.
When the edge needs to be sharper than merely 'sharp', the #13000 is the one you are after, it will be the final step for final finish planing, a paring chisel, fine cutlery and straight razors.
Here is a great video using the grid method to make sure your stone is perfectly flat before using it, this is very good practice and I suggest any person use this method until you get to know the behaviour of your specific stones and how they perform. https://www.youtube.com/watch?v=Dal4PZbJb2c
Another great video on honing a razor here; https://www.youtube.com/watch?v=nNXPKjVo_64&t=1022s
Product of Japan. Size 210x75x25mm.