Hi Slim, or is that Mr. Shady?

Thank you for your feedback. Open communication with our instructors often results in improved products and processes.
I hear what you're saying about our replacement O2 sensor cost, but let's first see if you are due any warranty credit. Did you know Analox offers a graded 3 year warranty on all Oxygen Sensors? It's the most generous warranty in the industry. While you can certainly purchase other replacement sensors for $85.00, they generally only carry a 1 year warranty. Essentially, you could be paying that $85.00 three times in comparison to a single purchase of an Analox replacement sensor at $130.00.
Please give me at call, toll free at 877 723-3247. We'll take a look at the age of your sensor and see if you are due some warranty credit on a replacement sensor. Your business and feedback is important to us. I look forward to speaking with you soon.
Safe and Happy Diving,
Patti L Clarkson
Vice President, Sales