The low-frequency interferometers (1 to 250 Hz) will use optics cooled to 10 K (−441.7 °F; −263.1 °C), with a beam power of about 18 kW in each arm cavity.[3]:15–16 The high-frequency ones (10 Hz to 10 kHz) will use room-temperature optics and a much higher recirculating beam power of 3 MW.[3]:15