Did you know that countries have different Z-Wave frequencies?
Z-Wave is a wired and wireless standard. On the wireless side, It uses a known frequency to communicate with other devices and controllers.
When buying Z-Wave products, you want them all to have the same frequency or they will not be able to communicate with each other. You should be able to check this frequency in the products specifications. If it does not say it, you should ask the seller if it is the frequency you need.
This should not mean much if you are buying your Z-Wave parts from a local supplier but if you like to shop on Ebay, Amazon and Alibaba, you may want to make sure your Z-Wave parts are working on the same frequency as your Z-Wave controller for your country.
For the USA and Canada this frequency is 908.42
Below is a chart with other countries and their freq's
If you would like to know more about Z-Wave and Zogbee (Another communication standard), here is an informative article.