Don't Need to say much these are the Arctic 140mm P14 PWM PST Fans… Kept an eye out after seeing the previous Arctic F12 120mm.
Description From Amazon:
OPTIMIZED FOR STATIC PRESSURE: Fan guarantees extremely efficient cooling, even with increased air resistance, therefore, the P14 PWM PST is particularly suitable for use on heat-sinks and radiators
200 TO 1700 RPM REGULATED VIA PWM PST: Thanks to 4-pin connector, the RPM can be regulated in a broad spectrum via PWM, noise is kept at minimum while maximum cooling performance is given when needed
MORE EFFICIENT TECHNOLOGY: The motor is powered by a Neodym-Iron-Boron-Magnet ring of the newest generation, which allows the new P14 PWM PST to run much more efficiently than its predecessors
EXTENDED LIFE SPAN: A 10 °C lower motor temperature roughly doubles the life span of a fan, the new ARCTIC motor has a four times longer service life through its low coil temperature
TECHNICAL DATA: Fan speed: 200–1700 RPM, Airflow: 72.8 CFM/123.76 m³/h (@ 1700 RPM), Noise Level: 0.3 Sone (@ 1700 RPM), Pin: 4-pin