Sperzel USA is a company based in Cleveland, Ohio, specializing in manufacturing custom tuning machines for guitars and basses. Since 1977, Sperzel has been known for its precision machining and unique design of tuning keys, with a focus on improving guitar tuning capabilities. Their Trim-Lok locking tuning key system eliminates the need for multiple wraps around the string post, enhancing tuning stability and ease of string changes. Sperzel's products are made in the USA, with parts manufactured in Cleveland and assembly done by American workers, reflecting their commitment to quality and American craftsmanship.