The Master Key Chromatic Pitch Instrument by Kratt is a compact tuner with 13 keys from F to F, designed for use with various musical instruments such as piano, cello, violin, ukulele, and more. Made in the United States, this black instrument comes in a bag/case for easy portability and storage. Perfect for musicians looking to ensure accurate pitch and tuning during performances, this chromatic pitch instrument is a versatile tool for any music lover.