This binary wristwatch displays the time in the language of computers, the binary system! If you press the button on the side, the LEDs light up to indicate the current time. All you have to do is add up all the glowing LEDs: The top row stands for the hour, from left to right the numers are 8, 4, 2 and 1. The bottom row shows the current minutes and the LEDs stand for 32, 16, 8, 4, 2 and 1. Power supply: CR2032 button cell (included, replaceable) Material: plastic and metal Circumference of the bracelet is adjustable from 14cm to 21cm