NEW YORK ( TheStreet) -- When those nifty smartphone key finders like Hone sprung up last year, the bummer for many of us was they didn't work with our Android smartphones. That's because only the Apple ( AAPL) iPhone had the necessary Bluetooth 4.0 technology, which is marketed as "Bluetooth Smart," and the majority of smartphone users don't have an iPhone.Google ( GOOG) finally caught up and over the summer it added Bluetooth Smart support to the new Android 4.3 operating system. Now, even Android owners can do such cool things as use their smartphones to unlock their doors, control a garden's sprinklers, wear a smart watch that says what's on the smartphone and, of course, quickly find misplaced keys. Well, almost. You've got to be careful. If you want this new feature, an Android smartphone needs two things: Android 4.3 and Bluetooth Smart. Those devices are slowly trickling out now. Some have had the hardware but are still waiting on service providers to roll out the Android update. AT&T ( T) subscribers with the HTC One started getting the update this month with more phones on the way. Verizon Wireless ( VZ) started rolling it out this week. Sprint ( S) is reportedly next. "Carriers don't always push out the new OS," warned Errett Kroeter, director of global industry and brand marketing for the Bluetooth SIG organization. "Look for devices that are shipping with Android 4.3 on them. If you are buying a new phone, it would be highly unlikely that the hardware component" wouldn't be included. Bluetooth Smart's appeal offers three major features. Smart refers to low-energy consumption, fast 3-milli-second connections and an architecture for developers to build apps. The most touted feature is its low-energy use, which has a greater impact on the devices that connect to smartphones rather than smartphones themselves. Kroeter said a good example of power savings is in watch-sized batteries. Instead of devices lasting a month on AA batteries, they can last a year by switching to a smaller, slimmer battery with Bluetooth Smart. Some of the Android phones with the new Bluetooth hardware went on sale earlier this year, well before Google added Bluetooth Smart support. (Windows 8 and BlackBerry 10 operating systems also support Bluetooth Smart.) Those manufacturers had to come up with their own Bluetooth fix but since it wasn't standardized, app developers waited for a more universal Android to add it.