The Binary Slider from One is a leather-strapped watch with two faces. An analog clock dominates the left side, while a binary-based digital counterpart is on the right. Switching between both faces is a simple matter of sliding the washed metal cover to either side.
The analog watch is enough to read, but the digital clock needs some unconscious algebra to interpret properly. Two columns of LEDs with numbers beside each one represent the hour (1, 2, 4, and 8) and minute (1, 2, 4, 8, 16, and 32) values respectively. To tell the time, the user has to add the numbers with lit LEDs. An example: with the 1 and 2 on the hour column and the 2 and 4 on the minute column lit up, the time is 3:06.
The watch isn't available to mainstream customers, only to wholesalers willing to buy in bulk.