MATERIAL: The sound hole cover is mainly made of high quality wood, eco-friendly and durable for long service time. SOFT: The guitar sound cover contains sponge material, soft and elastic, 't hurt the surface of guitar, not easy to break. FUNCTION: The acoustic guitar sound cover can eliminate unwanted feedback and enhance stage volume without disrupting placement or performance. Helpful to protect the sound hole. EASY TO INSTALL: Small size and light weight, weight is approximately 31-34g. The guitar sound hole cover is convenient to store and use, easy and quick to install and remove. Requires no modification to the instrument. Specification: Condition: Type: #1 Suitable for 41 inch Acoustic Guitar Aperture Outer Diameter: . 105mm / 4.13inch Inner Diameter: . 89mm / 3.5.inch Thickness: . 9mm / 0.35inch Weight: . 31-34g Color: wood color Material: Package Contents: 1 x Guitar Sound Hole Cover (Guitar is not included) Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.