Features: A set of three sizes (large, medium, and small) that perfectly meet the tuning needs of a piano tuners. Insert between the gaps where the stopping string is needed during use to prevent other strings from producing sound during tuning and causing mistuning. Made from felt material, the texture is moderate in softness and hardness, without damaging the strings, and has a good sound stopping effect. Suitable for piano tuners, piano teachers, piano learners, and piano enthusiasts who need to tune themselves. High toughness and durability. Suitable for piano repair replacement parts. Specifications: Material: Felt Small Size: Approx. 9.5x3x1.3cm/3.74x1.18x0.51inch Medium Size: Approx. 11.5x2x1.3cm/4.53x0.79x0.51inch Large Size: Approx. 13x3x1.5cm/5.12x1.18x0.59inch Package Includes: 3pcs Piano Mute Blocks note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.