Fallkniven Flipstone® FS4 Sharpener Diamond/Ceramic

Length (folded): 112.8 mm / 4.44”
Length (unfolded): 190 mm / 7.48”
Diamond Grit: 25 micron
Ceramic Grit: 9 micron
Handle Material: Zytel with stainless steel bolts

The FS4 Flipstone® sharpener takes knife sharpening to the next level with its innovative design and advanced materials. Featuring a combination of a diamond-coated stone and a ceramic stone, this sharpener provides a versatile and efficient solution for maintaining razor-sharp edges on your knives. The diamond stone, coated with Titanium Alumina Nitride, is perfect for heavy sharpening, while the ceramic stone, made from synthetic sapphires, excels in fine honing and finishing.

Both sharpening surfaces are extremely hard, with the diamond side measuring 10 and the ceramic side 8 on the Mohs scale of hardness. These materials retain their flat surfaces, making them ideal for sharpening even the hardest specialty powder steels. The stones are securely bonded with 3M tape for maximum durability and stability.

Designed for portability and convenience, the FS4 features a spring-assisted folding mechanism that allows it to unfold and lock into place with ease. It can be used dry or cleaned with soap and water for long-lasting performance. Over time, the diamond surface will smooth slightly, enhancing its effectiveness.

Instructions

Hold the Flipstone in your left hand. Push the catch on the upper section of the handle forward and press the exposed round button. A steel spring will automatically unfold the sharpening stone and lock it into position. To retract, press the round button and collapse the stone by hand. Fold back the catch to secure the sharpener and prevent accidental unfolding.