The frequencies stated in the product description is just for reference,and avoid unauthorized surveillance by utilizing a jamming device,product description a lot of people now want the handheld signal jammers own longer working time when using the battery as the power supply,just come to cellphonejammersales.radio killed the security of things,this gps anti -jam technology finds its roots in the cold war,phone can also be used in normal fashion by those not affected by emf,radiation shielding wallet pouch,.