I'd suggest you provide the full prompt as well as your own suggested answer. You're likely to get more out it this way.
You need to provide more information so that I can perform the calculation. With the information at hand, you can only calculate the revenues from a single customer (assuming the filters will be replaced every 6 months).
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You haven't given us nearly enough information…
We need the size of the market and/or we need to know the # of air purifiers sold