This is a reed adjustment stone. The abrasive is fine for micro-adjustments. It's a tool to revive unusable or difficult-to-use reeds, such as those that are too thick and hard to blow, uneven, or have absorbed water and expanded. Adjust by rubbing the flat part of the reed against it, as shown in the second photo. Even though the back of a reed appears flat, it's said to have microscopic irregularities, and these can have a negative impact. Just one swipe of the reed on this stone can change the sound and feel. Size: 11.5cm long x 3.8cm wide x 1.6cm high It's large enough to comfortably use with large reeds, such as those for bass clarinet and baritone saxophone. This product is made by a domestic specialist manufacturer and finished with very high precision in terms of flatness. The offering is for the stone only. The reed in the photo is not included. Type: Saxophone Type: Clarinet