Power: Receiver: 4 AA batteries; Transmitter: 12v 23A battery Range: 150 meters (492 feet) The receivers are very economical. They can be used independently. If one fails, the others will continue to operate. This system is expandable. Simply purchase more receivers from the website below. The receivers come pre-programed for your convenience however they are reprogrammable. Locate a small hole in the center of the receiver and insert a paperclip or similar object. The receiver will flash then press a corresponding key on the remote. Now the receiver has been paired with the remote. Caution! 1. Handle your product with care avoid shaking and dropping it. 2. Keep the receiver as far away from your fireworks as possible to avoid damage. 3. Remove batteries before storage. 4. Store your product in a clean dry area away from containments. Frequency: 433MHz This device complies with part 15 of the FCC Rules. Operation is subject to the following two conditions: (1) This device may not cause harmful interference, and (2) this device must accept any interference received, including interference that may cause undesired operation. color:As shown Material:plastic Package Contents: 4 x receivers 4 x transmitter Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.