Abstract: A mask includes a cover body, a first fan, a second fan and an air filter. The cover body has an air inlet and an air outlet penetrating through the cover body. The first fan is disposed on the cover body and matches the air inlet. The second fan is disposed on the cover body and matches the air outlet. The air filter is disposed on the cover body and partially overlaps the air inlet. The first fan drives an air-flow to rapidly flow from the atmosphere into the mask through the air inlet and the air filter. The air filter removes the particulates and the harmful substances in the air-flow. The second fan drives the respiratory gas to rapidly flow from the mask to the atmosphere through the air outlet. Therefore, the user is able to breathe comfortably with non-particulate and clean air.

Abstract: A mask includes a cover body, at least one first fan, at least one second fan and an air filter. The cover body has at least one air inlet and at least one air outlet. The at least one air inlet and the at least one air outlet penetrate through the cover body. The at least one first fan is disposed on the cover body and matches the at least one air inlet. The at least one second fan is disposed on the cover body and matches the at least one air outlet. The air filter is disposed on the cover body and partially overlaps the at least one air inlet.

Abstract: A wireless transmission device includes an audio fetching module, a storage module, a processing module and a wireless transmission module. The processing module electrically connects to the audio fetching module and the storage module, and the wireless transmission module electrically connects to the processing module. The audio fetching module acquires an audio signal. The processing module either stores the audio signal in the storage module or reads out the stored audio signal when being enabled. The wireless transmission module enables the processing module and transmits the stored audio signal according to the transmission enabling signal.

Abstract: A measuring device includes an audio collection module, an audio player module and a switch module. The audio player module electrically connects to the audio collection module, and the switch module electrically connects to the audio player module. The audio collection module collects sounds to generate an audio signal. The audio player module plays the audio signal. The switch module sets an enabling signal for controlling the audio player module. The enabling signal is set to be at either a first state or a second state different from the first state. When the enabling signal is at the first state, the audio player module plays the audio signal under a first output mode. When the enabling signal is at the second state, the audio player module plays the audio signal under a second output mode different from the first output mode.