This metronome works with a 9 volt battery that is provided. You have 3 ways to monitor action: high tone, low tone + red LED flash (in practice mode to its minimum). The sound setting is simple: a wheel on the side. A jack for connecting a headset: attention, she is not provided. Very stable since has a retractable foot, so it holds well even minimalist keyboard (which is not the case of some other metronomes to congestion more imposing style '' Piccolo '' which on some keyboards, with children may waltz ;-) Protective packaging adapted in the pack. Ease of use: translucent dial with arrow to the choice of frequency. Discreet aesthetic consistent with the picture (shiny black and red circle on a white background), small size (convenient for carrying in a pocket). In short, Seiko, reliable and efficient, with friendly price: 24,50 Euro. Maybe a downside for the height of digits (but hey, if it is small, numbering is also ... and then a '' Piccolo '' has a numbering equally small with a notch to slide more delicate finger of the smallest, and yet it is one of the most recommended by piano teachers). 24H Service Delivery by 'Premium' in suitable packaging. Product recommend, really.