Their national partners listed on the Innova website have over 1000 stores before you even consider Walmart and Play it again and every other dealer from the small service station to the golf clubs (some of which are doing $100'sk annually in turnover in retail sales on Innova alone I was shocked to find) to the pro shops near the heavy use courses.
From a retail perspective over here in the UK a retailer expects to make at least £1.5k a year on a square foot of space and will swap a line out for any less, I imagine it's fairly similar in the states, possibly swapping dollars to pounds 1 to 1 to equate with slightly lower land and rent prices.
Have a look at the racking in any of the national partner stores and work out how many foot of floor space has been allocated to Innova. Then use the dealer function on the Innova website to work out how many dealers there are around the country. You can see then the numbers are biiig. Retailers are not stocking product that doesn't shift. Innova has a looot of retailers.
All this before you factor in competitions/course installations/schools programs and crucially overseas sales which I would guess make up around 10% of turnover but growing rapidly.
I'm not convinced by as much as $52 million a year yet but I would buy $30m plus happily. With around 150 employees that equates to a turnover of 200k per employee which actually sounds about right for a growing manufacturing company