The Proton is a new generation 100% Digital Audiometer available in basic version the DX 3 and the diagnostic version the DX 5. This audiometer also features an optional user-friendly PC software, the Proton SX 3 and the Proton SX 5 with software is designed for unidirectional operation for optimal operating efficiency during daily routine examinations. New features incorporated into the Proton include, amongst other, data interface, ipsilateral masking, and simultaneous presentation of stimulus and masking binaurally. State-of-the art technology has enabled us to produce a compact lightweight instrument not only capable of performing the standard battery of tests but also featuring many other advanced and innovative facilities. All these features have been incorporated into a striking simple user friendly and ergonomic design, which makes operation fast, easy and efficient. Acompletely new attenuator which permits totally click free operation over the entire attenuator range. Simple menu-driven dialogue makes the PROTON easy to learn and easy to use. Working with menu driven display is uncomplicated, the display itself is easily readable under any lighting conditions and from any viewing angle thanks to state-of the-art LCD technology. The Proton SX software saves patient audiograms and sessions for recall, review and printing.