Calculating LT1 and LT2 approximately without a blood test?

Interesting that it doesn’t quote any data comparing it to a properly calibrated metabolic cart or similar. Also can a company such as this be viable just selling one product with no ongoing revenue stream via a subscription. Remember Humox muscle oxygen sensor and Oura ring went to a subscription model after 2/3 years. All the “reviews” I’ve found just seem to be regurgitated press releases. I’ll be watching it though with interest.