There are two basic types of amplifiers:
Direct Connect , they plug directly into your cellular modem (aircard) or cellphone.
Extenders, Repeaters, or Boosters that take a marginal WiFi signal, amplify it and rebroadcast it in your home, office, RV, or other vehicle.
All of these devices are dual band and will function with Sprint, Verizon, AT&T, T-Mobile and other 800mHz or 1900 mHz providers. They DO NOT support Iden (Nextel), LTE (on 700 mHz), or Wimax (2500 mHz).