Retevis H-777 Walkie Talkies UHF Long Range Rechargeable 2 Way Radio 16CH Portable Handheld Emergency Two Way Radios Set (10 Pack) They have been programmed to same frequency when out of the box and just on the same channel can communicate;Not work directly with H-777S Voice prompt function;easy to change the channel and easy to found your group channel Flashlight will make things handy in dark environment; and belt clip make them easy to carry Supporting USB charging(without adapter) will provide you more convenient when you need to work long time outside Simple and Convenient return process;1 year warranty and 30 day return with no questions asked