1. this low-noise cooling fan to prevent your for Nano board from overheating! 2. This black cooling fan is designed for the NANO board. 3. With stronger wind and better heat dissipation effect, the service life of the development board can be effectively extended. 4. The fan adopts anti reverse connection interface to prevent the user from damaging the board by mistake. 5. We also 4 screws to fix it on the for NANO board. Product name: cooling fan Size: 40 x 40 x 10mm Wire length: 8cm Rated voltage: DC 5V Starting voltage: 4V Rated current: 0.15±0.02 Rated speed: 4800rpm±10% Life: 25℃,20000 hours Polarity protection: The circuit is not burned when VCC GND is connected in reverse Operating temperature / humidity range: 10℃~ + 60℃ / 35% -85% RH color:Black Material:ABS Package Contents: 1 x for Nano A02/B01 cooling fan Only the above package content, other products are not included. Note: Light reflection and different displays may the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.