Make me a reasonable offer as I no longer have use for this, it works fine and just needs the battery replaced.

The Oxy 2 is a semi closed circuit rebreather sensor/transmitter for use with the Aladin Air Z O2 computer. Features: Designed for exclusive use with semi-closed rebreathers Dual sensors Independently calibrated system inserts in gas flow of rebreather inhalation hose; incorporates two Oxygen sensors that can be independently calibrated. Aladin Air Z O2 Compatibility When paired with Aladin Air Z 02, system transmits actual Oxygen content of inhaled gas to wrist unit.