Abstract: A mouthpiece, comprising at least one inlet configured to allow oral fluid from a user's oral cavity to travel into the mouthpiece; and a reservoir comprising one or more chambers, the reservoir configured to store oral fluid received from the user's oral cavity through the at least one inlet, wherein the mouthpiece is configured to be contained substantially within the user's oral cavity during the collection of oral fluid.

Abstract: A loudspeaker is described with two closely spaced diaphragms simultaneously driven by the two ends of an actuator. By balancing the impedance load of both diaphragms on the actuator both diaphragms radiate in phase and hence improve sound reproduction and efficiency of operation.