The Poseidon brand Oxygen Sensor is used for the MKVI and Se7en rebreathers. The Poseidon brand sensors are manufactured by Analytical Industries (AI) and identical in all respects (other than the label) to the AI brand PSR-11-39-MD. Because of our high sales volumes for the AI versions we do stock, the AI versions are always of very recent manufacture.Features: Accuracy within +/- 2% of full scale Response time is 6 seconds Conformal coating Temperature compensated Hydrophobic membrane