I don't see Locket available on app stores, but maybe you can get it direct am not sure... Am not a fan of these apps, they drag your phone performance way down and personally i find lock screens a HUGE pain in the bahooky. I did have a few passive earning ad apps on phone for a few weeks, but, just couldnt handle how laggy the phone got, and as i use my phone a lot for task apps it was trebling the time it took to do a task, so, they were all binned... think in nearly a month over about 6 apps i made 87p or so.. really not worh it if you like to use your phone... if you have an old smartphone that still works that you no longer use, thats what you could put these on (even without sim they work i believe, using wifi) and just let them drag it down since you dont use it.