Assisted grip to achieve the correct relaxed contrabus bow grip Even a beginner can hold a bow without having to worry about it from the beginning. This revolutionary bow-aids for contrabus helps you learn how to hold the bow correctly and quickly. One size fits all from small children to adults. Easy to install and remove. Ergonomic Design Gently conforms to the shape of your hand for flexible contrabus grip. Maintains optimal form to develop right hand finger balance, keeping your hands and arms flexible from the early stage of learning, allowing you to focus more on sound making and music. The Wada Yunbow aids are one size fits all. Suitable for small children and adults Learn the correct bowing without having to harden your arms. The index finger and pinky finger are touched directly to the bow to respond to the natural bow movement. With the Wada-Yo Aid, you can use your arms correctly and freely from the bow to the tip.