The tu300 gives you 7 different tuning modes including regular flat double flat and chromatic mode a precise 7 segment led and 11 point stream meter guarantee accurate tuning you can adjust the reference tone in the range between 438 and 447 hz plus there is a mute function for silent tuning we have also included a status led for effect on off and battery check and you can run your tu300 on a 9 v battery or a dc power supply not included