NMB Technologies IP55 Tacho Output Brushless DC Fans offer a 12V to 24V voltage range, 0.8A maximum current, and a 6000 RPM maximum speed. These NMB Technologies fans feature a DC brushless motor, meet the IP55 ratings per IEC 60529 standards, and have a long life and high reliability with NMB rust-resistant precision ball bearings. Motor protection is achieved through auto-restart and polarity protection, so the motor withstands reverse connection for positive and negative leads. NMB IP55 DC Fans have an open-drain tacho signal output for fan speed.