I owned the Z Force initially and it has a great internal battery so I didn't have to rely on the battery mod all that much unless I knew I'd be away from a charger for over a day. So I was able to use the JBL Speaker a good bit. With the Z I've found myself hardly ever taking the battery mod off bc the internal battery runs out so quickly. It's one reason I'm thinking about sending it back for a refund and getting the Nexus 6p in a 64g. I was just curious if you guys also feel like it's needed at all times like I do. The first couple of days my battery mod had not been delivered yet. It seemed like I could barely make through 3/4s of a day with just the internal battery by itself. I was expecting a bit more battery life out of the Z. It makes the other mods almost useless if your away from a charger for a full day. I'm still on the fence about exchanging it bc it is a very good device but I'm amazed at how much of a difference the Z Forces battery was coming compared to the Z.