In this video, Motley Fool Stock Advisor analyst Jim Mueller discusses three areas that SodaStream (SODA) investors need to watch.

As SodaStream is a "razor and blade" model, investors need to look at the unit sales of "razors," that is, the soda-making machines, since the growth in the sales of the machines will lead to a growth in sales of higher-margin "blades," or the syrup and CO2.

Investors should also keep an eye on the "blades" themselves; we should see the sales of these consumables rising as the company grows and penetrates new markets.

Lastly, investors should look at the number of locations where the devices and, most important, the CO2 cylinders are available. As the CO2 cylinders run out, consumers need to replace them. Some people stop using SodaStream machines because these cylinders are not available at convenient locations. If the trip to get these cylinders is around 15 minutes, it is likely that consumers might switch back to regular soda cans and bottles.