The first version of Nexus 6 has a cool feature named “Double-tap to wake” to wake up. The function which looks like HTC One M8, that somehow has been deleted by Google before this handset officially released to public. It is not clear enough about the reason why Google do that. But if you have rooted Nexus 6, you can get the feature “Double-tap to wake” back by this simple application.
Having a feature “Double Tap to Wake” on your smartphone must be very amusing. It might need more struggle to find this for your Nexus 5, but you will find it is much easier for Nexus 6. On Nexus 6, you just need simple steps to get this feature.