1No power required. 2No need to change any part of the original walkie-talkie, just take two handheld walkie-talkies, then it can work. 3Use two hand-held walkie-talkie headset jacks to form a very practical small repeater through this relay box. 4User friendly design, easy to operate. 5Small and portable.Features:No power required. No need to change any part of the original walkie-talkie, just take two handheld walkie-talkies, then it can work. Use two hand-held walkie-talkie headset jacks to form a very practical small repeater through this relay box. User friendly design, easy to operate. Small and portable. Specification:Type: Portable Relay BoxPlug: M head (Note that it is M head, NOT K head.)Distance; 5-8 km from open space, 1-2 km from densely populated buildingsWhether it is two-way: yesLine length: 90cm on the left and 90cm on the right(about)Material: ABSColor: BlackWeight: Approx. 70gWorking Mode:1. Different frequency uplink and downlink forwarding: A machine as a signal uplink receiver, B machine as a signal downlink transmitter, to reach the purpose of relay.2. Two-way forwarding: A machine receives while B machine is transmitting. B machine receives while A machine is transmitting. (To achieve two-way forwarding function.)3. Adopting audio trigger mode, so the volume of intercom receiver should be adjusted to the maximum when in use.Package list:1 * Portable Relay BoxNote:1. For one-way relay box forwarding mode (conventional repeater mode) A machine receives the signal, B machine sends the signal. The receiver / transmitter must be set to two different frequencies. The frequency of the conventional transmitter is higher than the receiver frequency. Usually, the high / low frequency difference is 10 M. The higher the frequency difference, the better.2. For one-way relay box, please do not inversely connect the jack, otherwise the relay box will not work.3. For two-way relay box, regardless of plug input / output; two-way relay box forwarding mode: A machine receives when B is transmitting, B machine receives when A is transmitting.4. Adopting audio trigger mode, so the volume of intercom receiver should be adjusted to the maximum when in use, or there may be non-forwarding state.5. If the transmitting delay time is too long (more than 3 seconds), because of the radio transmitter antenna too close to the relay box, you can solve the interference problem by an external radio antenna.6. Note that it is M head, NOT K head.7. Please note that walkie talkie is NOT included, ONLY a reply box.8. Please allow slight err