Abstract: A wearable article for detecting an impact to the head is provided. The wearable article includes a first flexible layer and a second flexible layer. A sensor is disposed between the first flexible layer and the second flexible layer. An indicator device is operably coupled to the sensor, the indicator device being configured to to provide a visual indication of the level of the impact.

Abstract: A dive valve quick release connector includes a flat plate having a flat arm extending upwardly therefrom. A mechanism on the flat plate is for securing the flat plate to a buoyancy compensator waist strap. A mechanism on the flat arm of the flat plate is for removably attaching a valve block thereto. The valve block is connected to: a first low pressure hose from a main scuba tank via a one way check valve, a second low pressure hose from an emergency bailout scuba tank, a knob assembly, a third low pressure hose to a dive mask, and a dry suit inflator hose.

Abstract: This invention is for a percussion instrument that when struck produces a sustained tone. The instrument is shaped to produce a harmonious tone by tuning the appropriate overtones. The fundamental tone generated by the instruments disclosed herein are controllably tunable to within fractions of a hertz (Hz). Also disclosed are instruments that minimize and dampen unwanted overtones to generate a substantially pure tone. Also provided are related methods for generating a sustained tone as well as methods and devices for generating a beat, wherein a pair of the percussion instruments of the present invention having different tone frequencies provide the beat.