This little gem simply keeps phones from talking to their towers, preventing annoying ringing, calls, and text messages. It does not interfere with any services other than cellular within the device's range. After activating the blocker, all phones will lose service. Any calls in progress will be terminated, as well as incoming calls. When turned off, all service will be restored. Simply charge the internal batteries as shown in the instructions and turn on the unit! It's that simple! No adjustments needed. When on, a light will turn on to indicate operation. When turned off, the light will go out.

Note: Effectiveness will be lower through walls and other materials. The coverage range varies with the proximity of the cellphone towers, and the obstacles between the towers and the blocker. This means that if the cellphone tower and the jammer are a large distance apart, the unit will have a large effective range. Alternatively, if there is a small distance between the towers and the jammer, the effective range will be decreased. Due to the internal antenna system, any body part or object covering the unit will decrease its range. The jammer will work great on phones in the immediate area of the user, especially if cellphone tower signals are weak. Placing it in or around any metal will act as a barrier and will decrease the range. This unit may not operate well if you are very close to a phone tower.