That’s the cooper 9500 “anywhere” battery operated switch. They should be widely available from the specialty Z wave retailers. Amazon also carries it.
Auction and second source sites
Sure, you can just look on eBay or BuyDig, but personally I prefer to buy from a place with a decent returns policy and a fair reputation. Too many reports of people buying from eBay and getting a different model than what they ordered (sometimes in the wrong box). Also note that some manufacturers (Aeotech is one) believe that everything sold on eBay is used and will not honor warranties for items purchased through this channel.
You can buy Chinese made items from AliBaba express. I myself don’t use this as a source – – too many issues with the product description, or even counterfeits. But a lot of people do.
Remember that for Zigbee, you want devices which are certified for Zigbee Home Automation 1.2 (ZHA 1.2). There are many Chinese zigbee devices wh…
Shop around, as prices vary a lot and Amazon isn’t always the least expensive.
https://www.amazon.com/Eaton-RF9500AW-Aspire-Battery-Operated/dp/B004I7YSVI
( Eaton is the company, Cooper is the division, and aspire is the model line. You may find it listed under any of those three names.)