These amplifiers are not only used in cell phones, but also increase reception in two-way radios, PDAs, walkie-talkies, beepers, and even cordless phones in your home. Upgraded Generation X PlusSP-1Revised Edition Antenna Amplifiers for Mobile PhonesOur new generation X Plus revised edition mobile phone antenna amplifiers are better than ever! The antenna amplifier is now stronger and has shiny gold. It also provides instructions for installing and testing your new antenna. Benefits:1) Huge impact-like having a 4 foot antenna on your cell phone.2) Improves reception, reduces static in boats, elevators, cars, buildings, tunnels, and mountains.3) Works on any analog, digital, and tri-band phones.4) Eliminate dropped calls.5) Easy to install, simply peel and stick to the inside of the battery compartment.6) Each amplifier is individually packaged ready to be given as a gift or for resale!" Installation is easy..! 1. Open the mobile phone and remove the mobile phone battery2. Remove the adhesive seal from the booster antenna3. Keep the amplification antenna inside the phone near where the phone antenna is located (check the user manual of the mobile phone.4. Put the phone battery back, close and turn onPacking List: 10 * SP-1 Mobile Phone Signal Boosters