This allows you to hook up all kinds of fun things as an input. It is an invention kit that tricks your computer into thinking that almost anything is a keyboard. The kit uses high resistance switching to detect when you've made a connection even through materials that aren't very conductive. The on-board ATMega32u4 communicates with your computer using the Human Interface Device (HID) protocol which means that it can act like a keyboard or mouse. size: 9.4cm x 4.8cm Material:PC colour:As Shown Package Contents: 1 x main control board 10 x spring clips 1 x Mini USB Cable 10 x jumpers Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.