This set is a must have for any person who is going to do a reasonable amount of sharpening on whetstones. The adjustable universal stand will fit most available whetstones and diamond plates, the stand holds the whetstone firmly in place to create a stable, elevated and comfortable workstation. The soft rubber mounts allows for secure footing of the stone, this avoids the stone or plate you are working on moving about as you work your razor on the stone. The #400 Atoma plate has two purposes 1) It serves as a medium for the heavy and quick removal of steel. If you have a a razor that is in bad shape you might have to remove a lot of stock to get to the stage where the entire cutting edge and spine lays flat on your stone, This is a basic requirement before you can proceed to set the bevel and proceed through a progression of whetstones, unless you choose to sharpen the razor freehand, a skill not many will master. 2) It serves as flattening plate for your other whetstones. As you work on the whetstones they will eventually develop a profile as stock and cutting medium is removed, the Atoma #400 mounted on its flat aluminium base can be used directly on the stone to return it back to a perfectly flat state, something I like to do every time I take a new razor to the stones. Here is a nice vid that will show you some good technique to sharpen your razors, and also shows how the Atoma #400 is used for both heavy stock removal and to flatten your honing stones. https://www.youtube.com/watch?v=nNXPKjVo_64&t=1022s Here is another 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