In an ejector cycle with an ejector including a nozzle for decompressing refrigerant, a control unit controls an air blowing amount of an evaporator fan so that a flow speed of refrigerant flowing in an evaporator becomes in a predetermined flow speed range. In one embodiment, a roller device may include a carriage or housing and one or more rollers coupled or integrated with the housing, configured to apply a protective material to a surface of the electronic device in a first orientation, and configured to function as a device stand in a second orientation. The transmission may be configured to self-shift between the low-speed, high-torque mode and the high-speed, low-torque mode in response to a change in a torque required to rotate the output shaft in both a clockwise direction and a counterclockwise direction. 0 \u03bcm parallel to a sliding direction upon connection, a mean projection-depression interval of from 0. In some embodiments, an audio headset that includes one or more electroencephalography sensors is provided.