US Patent 10510326 Bow grip aid for string instruments

A bow grip aid for string instruments comprised of a body having a U-shape in cross-section so as to be capable of sandwiching a stick of a bow, wherein the body includes a first portion and a second portion to sandwich the stick by the first portion and the second portion from both sides, a surface of the first portion has a recess corresponding to a thumb of a player on the opposite side of a surface contacting with the stick, a distance from a bottom of the recess of the first portion to a surface of the stick is 2 mm to 10 mm, a length of the second portion in a longitudinal direction of the stick is 30 mm to 50 mm, and a thickness of the second portion from a surface contacting with the stick to an opposite surface is 5 mm to 15 mm.