2 layer board of 1.55x1.63 inches (39.42x41.43 mm). Breakout board for arduino pro mini 3.3v or 5v, with an nRF2401+ connection. The board has an onboard 3.3v and 5v regulator. The nRF2401+ is connected to the 3.3v regulator of the board and not to that of the Arduino so the long range nRF2401+ modules can be used. Resistors and capacitors are 0805 size.