Worked for my Galaxy Note 3 and my Wife and Son's iPhone 4 and iPhone 5. Due to a loss of reception because of the KitKat update on my Galaxy Note 3 I now have worse reception. Zero bars where I use to have 1-3. How any company can release an update that takes away the core essential purpose of a phone which is communication is beyond me. This actually helped my Note 3. I went from standing in the exact same spot with barely a bar and not being able to receive a new text to getting 1-2 bars after installation and receiving and sending texts. Nothing else changed. For Galaxy Note 3 users, install this under your battery compartment in the upper left corner just under the contacts.
I live in a large apartment complex and can never get any bars inside my apartment. The instructions said that where there is never a signal, we can't expect any bars, I read and followed instructions for the cell boosters, put in 5 and now I can get up to 4 bars right here inside of my apt. I placed 2 on the back of my battery and 3 on the inside of the phone back. In an emergency I used to have to run outside in the freezing cold to try to get even one bar. I ordered them but didn't really think they would help much but this is beyond my greatest expectation.
I've done some testing with this on my phone and off my phone. This can possibly help signal in your device. I'll say these in my government building a lot of my colleges CAN'T get signal in the office and I have this on my phone and I do get service in that very same office which almost everyone can't. And I have a cheap prepaid cell phone that runs off the sprint network.
When I purchased the antenna boosters I was not even sure what they looked like. when it arrived it is simply a small sticker that you put inside the phone. Before putting the antenna in the phone, I was having a terrible time with dropped calls. But after installing it and, I have to admit I was at first skeptical that a small sticker like device would even work, I was amazed at how much a difference it made.
I had bought these antennas a while ago to help with cell phone reception (they did work). The antennas do give me a few extra bars which is nice.