Virtuoso Wrist Practice Aid for Violin The shape of the end (metal fitting) is different from the last photo. Tape is wrapped to prevent it from coming off. It is for 4/4-1/2 size, but it can be adjusted with Velcro, so it can also be used for children's hands. Retail price: 2800 yen Developed by Aaron Lockwood, a violinist who made his debut with the Chicago Symphony at the age of 12. It has a function to prevent the wrist from bending easily when you are off guard. If you use the correction device wisely, your bad habits will be corrected. I haven't used it much and have graduated from it, but it is a used item, so please purchase it only if you understand.