The product does what the manufacturer says it was designed to accomplish. The signal booster, at least carefully place under the battery of my phone, -according to the detailed instructions on the package, allow me to get service in places it didin't before, except inside the elevator, and with the door closed; but, after all, the product is designed to multiply a signal, -if the there's no signal, or close to none, it takes very little mathematical knowledge to expect no improvement (a X 0 = 0)