A hydrogen gas indicator system that provides various substrate materials that support hydrogen gas sensor materials with discrete indicia that provide information separate from any change in the physical properties of the hydrogen gas sensor itself. In particular, the instant invention relates to large diameter introducer catheters having increased strength, flexibility, and kink resistance. In a preferred embodiment the infra-red dots encode sound recording data associated with the visible light image. A set or reset may be armed while the clock signal is low, and the set or reset is triggered at the rising edge of the clock. Also selected fractions from the sample can be applied to a patient, either alone or as part of a mixture. The method also includes waiting to receive a ready indicator and communicating with the slave device in response to the ready indicator.