An easy-to-use accurate audio/visual tuner for your guitar. Provides a simple interface to visually check whether the pitch for each string is low or high, and lets you "see" the pitch change as you wind/unwind the string tuning machines. ? Standard Tuning E-A-D-G-B-E based on concert pitch A440. (The International Organization for Standardization specifies the frequency for the note A in the treble stave as 440 Hz. ISO 16:1975) ? Accurate within 5 cents of note (very accurate) ? Developed in Austin, Texas, the "Live Music Capital of the World". ? Instead of visual tuning, just tap if you would like to hear an accurately tuned note.