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.