50 x 50 x 10 mm Quiet cooling fan, 5/12/24v, 3000±10% RPM, 11.89 CFM, they are durable and you don't need to buy another small fan in the next 70,000 hours Precision Bearing: High precision, long life and low noise sleeve bearings are adopted. High temperature resistance, stable operation, long service life. 5/12/24V DC fan Dual Ball Bearing Thermal Fan,2pin,UL Certified, Long life ,Low Speed,Quiet Wide Range of Applications: Use these 23 dB cooling fans to get near-silent operation. Suitable for hot end cooling, ideal replacement for 5/12/24V 5cm fans in 3D printers, DVD players, small communication devices for heat radiation, PC CPU server, DVRs, switches, cooling capacity, other network and storage devices, etc Strong Wind: 2Pin DC Cooling Fan, the high-intensity fan blade design uses a powerful wind pressure to concentrate the airflow through the concept of providing a powerful airflow for your machine to cool properly,