I had a look at the product myself.

Pretty straight forward.  Small bar fridge size.  Heats peroxide, sterilises unit in about 6 minutes and waste products are just water and oxygen.

Could easily be addapted for other uses.

The caveat being that, by those in the field, this level of sterilisation is not to a surgical standard.  For those purposes, there are better but more expensive devices.  NAN have done a great job at capturing this market for medium level sterilisation.  There should be plenty of other products out there in this market for NAN to capture.

 I'm questioning whether 2017 results were just an anomoly.  The significant drop in ROE for 2018 is concerning.

I like the business more having seen Strawman's straw on business model.  Not only does the product offer 30% recurring revenue from sale but the expected life of the product being only 4-5years offers the potential for exponential growth prospects should the product hold its position as the market leader.