1、Four rings are placed on the slide rail, designed to expand fingers\u0027 gap for large span tune playing. 2、You can easily adjust the trainer finger rings to appropriate distance with scales to fit your finger via screws. 3、Thick rubber and round edge rings can protect fingers more from long time exercising stress. 4、Widely applicable for guitar, bass, ukulele, piano, cello, viola, violin, flute and wind instrument, etc. 5、Light-weight and easy to use, great practice assistant for instrument new beginner. Features: Four rings are placed on the slide rail, designed to expand fingers' gap for large span tune playing. You can easily adjust the trainer finger rings to appropriate distance with scales to fit your finger via screws. Thick rubber and round edge rings can protect fingers more from long time exercising stress. Widely applicable for guitar, bass, ukulele, piano, cello, viola, violin, flute and wind instrument, etc. Light-weight and easy to use, great practice assistant for instrument new beginner. Specifications: Brand: Flatsons Model: KZ-01 Color: Black Material: Plastic + rubber Dimension: 19 * 4.5cm / 7.48 * 1.77in Net Weight: 69g / 2.43oz Package Size: 24 * 10.5 * 3.5cm / 9.45 * 4.13 * 1.38in Package Weight: 99g / 3.49oz Package Size: 1 * Guitar Finger Expansion 1 * Backup Screw 1 * Guitar Finger Expansion 1 * Backup Screw