Features: Easy sharpening and polishing all kinds of exact knives. For sharpening and polishing chilled steel,alloy steel and precision parts etc. If you install it in the sharpener system(same the system in our shop), you can buy the whetstone that Stuck on the base. Please notice that there are different price for different stone,you can just select categories. The whetsone size is 150mm*20mm*5 mm,The base size is 157mm*21mm*4mm. As are natural stone, some stone has other color like black or white dot etc, please pay attention Chromium Corundum Whetstone (200 Grit) Green Carbon Whetstone (400 Grit) Boron Carbide Whetstone (800 Grit) Black Onyx Whetstone (1500 Grit) Ruby Whetstone (3000 Grit) White Agate Whetstone (6000 Grit) Natural Green Whetstone (8000 Grit) Natural White Whetstone (10000 Grit) Color: Red,Yellow,Green,White,etc Material: Chromium Corundum,Green Carbon,Boron Carbide,Black Onyx,Ruby,White Agate,Natural Green,Natural White Size: One Size Length: 15cm (5.90in) Width: 2cm (0.78in) Height: 0.5cm (0.19in) Quantity: 1SET Note: Size for manual measurement, there may be a 0 to 2 for cm error, belongs to the normal phenomenon. And due to the difference between different monitors, the picture may not reflect the actual color of the item. Thank you! Package includes: (Without retail package) 1 SET Sharpening Stone