I'm using iOS. My understanding is that for iOS you need a wifi one and for Android you need a Bluetooth one. I have this one (
http://ebay.eu/2bChgYe) but be aware, if you want to use some of the more advanced features of Carly you need to buy their adapter which is quite pricey in comparison. It looks exactly the same as some of the other cheap ones on eBay/Amazon but it's not. I know this because I've bought the another cheap one which looked identical and had what appeared to be exactly the same spec as the official Carly one but it didn't work with the more advanced features. The cheap adapters still work fine for fault code reading/clearing and most of the coding options. Just can't mess with some of the security and safety parts of the ECU (I'm not sure why you'd want/need to anyway).