Efficient Portable Piano Tuner - Lightweight and convenient. L-shaped design makes it easy to use and comfortable to carry. Well made with precise force to tune your piano without damaging the instrument. Suitable for most upright pianos - This L-shaped tuning key grip with nickel-plated metal handle fits the pins on standard 3/16 \" hitch. The tuning hammer hole size is approximately 0.65/0.26 inches. They can work very well on most studs. Save your valuable time - If you are a piano lover. Do you often find it difficult to start with a grand piano? These L-shaped piano keys can definitely help you. Helps you simplify all steps. Save your precious time. L-shaped design - The L-shaped design of the adjustment hammer is more in line with artificial body science. It is more comfortable to hold. Does not cause pain in the hands due to prolonged grip. Premium and durable material - The metal shaft of the tuning key is made of hard steel. Abrasion resistance, small and exquisite, convenient to carry. Durable enough for long-term use.