The CB6 allows the subject or experiment supervisor to provide simple responses to stimuli presented by ViSaGe or Bits#. Six high quality buttons mounted on a robust hand-held box can be used to respond in a range of ways, including simple forced choice or gradual parameter adjustments when finding thresholds. The CB6 interfaces directly to ViSaGe or Bits# via an infra-red link, and supports a high-resolution counter to measure reaction times.