Unused spares. Vernier Respiration Monitor Belt RMB for training purposes only. The Respiration Monitor Belt is used with Vernier Biology Gas Pressure Sensor (not included) to measure human respiration. Attaches to the Vernier Biology Gas Pressure Sensor which is then connected to any of the Vernier Interfaces such as ULI, MPLI, Serial Box Interface or Voltage Input Unit as well as the Texas Instruments CBL. (None of these interfaces or pressure sensor is included. They are always sold separately). Sale is for the Respiration Monitor Belt and User Manuals ONLY as shown. There is nothing else included.