[gjm11]

> take only 1% of 1% of 1%

1. Why? I mean, I get that it's a very small fraction, but if you're considering a scenario where you only get a very small fraction of the market, why should that very small fraction be more plausible than, say, 1% of that?

2. OK, so the population of the world is about 7 billion, and 1% of 1% of 1% of that is 7,000. That's not actually so very enormous, especially as you're not going to get a lot of recurring business. (Unless you're envisaging that people pay on a subscription basis for the continued use of the locks on their home, in which case I think 0% of 0% of 0% is a better guess for the likely market penetration.)