Lian Li PT-FN04 Black Fan Speed Controller 6 sets of Fan Speed Controller, Using 1 x 5.25 Bay. adjust the fan speed to (H) High-100%, (M2) Middle-75%, (M) Middle-50%, (L) Low-25% 1000RPM (250RPM - 500RPM - 750RPM - 1000RPM), 1200RPM (300RPM - 600RPM - 900RPM - 1200RPM), 1500RPM (375RPM - 750RPM - 1125RPM - 1500RPM) Dimension:(W)149mm x (H)42mm x (D)72mm