Features: It can swing with rhythm and add a different accompaniment when playing guitar. Good quality stainless steel ring bells will not fade or rust. sound resonates deeply and is clear delicate and pleasant to listen to. Designed with silicone protector on both sides no harm to guitar. Press-on design for easy and fast installation no tools required. Retractable back and forth design adjustable for sound hole at various diameter. Adjustable height without affecting playing and singing. Specifications: Model: MB20 / MB20L (Optional) MB20: Material: Alloy+SS Bell Quantity: 10pcs Soundhole Size: Suitable for soundhole in 80-100mm diameter Guitar Size: Suitable for guitar of 36/38 inches Item Size: 112 * 43mm / 4.41 * 1.69in Item Weight: 53g / 1.89oz Package Weight: 107g / 3.80oz Package Size: 15.5 * 6.5 * 4.5cm / 6.10 * 2.56 * 1.77in MB20L: Material: Alloy+SS Bell Quantity: 12pcs Soundhole Size: Suitable for soundhole in 90-115mm diameter Guitar Size: Suitable for guitar of 40/41 inches Item Size: 125 * 43mm / 4.92 * 1.69in Item Weight: 63g / 2.24oz Package Weight: 114g / 4.02oz Package Size: 15.5 * 6.5 * 4.5cm / 6.10 * 2.56 * 1.77in Package List: 1 * Tambourines 1 * Manual (English)