Specification: Features: 1.Rechargeable: guitar tuner comes with a battery, which will last 10 hours on a single charge. There's also a battery level indicator on the display. Has an auto off mode to help conserve the battery after 5 minutes of inactive use. 2.Tuning Range: this little tuner is capable of tuning not only guitars, but also chromatic, ukuleles and violins. there39;s a tuning range of between a027.50 hz and c8 4186.0 hz. It39;s the largest range ever as guitar tuner on amazon. 3.Accurate Stable: accurate to 11000th of a semitone or 11000th of a fret. guitar tuner built in pickup to help blocks out any background noise that might interfere with tuning. 4.Features Piezo Sensors: which are highly sensitive coupled with a micro processor for fast and accurate tuning. 5.Easy to use: select your mode and start tuning. the guitar tuner will show yellow if the note is flat, red if the note is sharps and blue if you39;re accurate. Specifications: Tuning range: A 27.50 Hz-Ca 4186.0 Hz A4 value range: 440Hz Tuning items: Twelve equal temperament, guitar, violin, ukulele Tuning accuracy: 1 cent Power supply: rechargeable battery Size: 49L26W40Hmm Accessories: instruction manual, charging cable Notice: Due to the different monitor and light effect, the actual color maybe a slight different from the picture color. Please allow 5-30mm differs due to manual measurement. Package List: 1 x Guitar Tuner 1 x Charging cable 1 x User manual