1. perfect FOR BEGINNERS: perfect for 4/4-3/4-1/2 violin , great for beginners to master correct bowing action and violinists to improve their playing skill. 2. SELF TEACHING ACCESSORY: Self bowing practice guide and it help you cultivate correct bowing and wrist action. 3. MINI SIZE: light weight, easy to put it into your violin case. 4. FIRM AND STRONG: in use, easy to install and disassemble, attaches easily, and in seconds.difficult to break off, wearable, no harm to your instrument. Material: carbon fiber colour: black Package Contents: 1 x Carbon fiber straight bower Only the above package content, other products are not included. Note: Light reflection 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.