About Optional: I. Just one Button: no receiver ,It cannot be used alone. II. White1x1: Color White 1 button 1 receiver III. White1x2: Color White 1 button 2 receiver IV. White1x3: Color White 1 button 3 receiver V. White2x1: Color White 2 button 1 receiver VI. White2x2: Color White 2 button 2 receiver VII. White2x3: Color White 2 button 3 receiver VIII. White3x1: Color White 3 button 1 receiver X. White3x2: Color White 3 button 2 receiver 1.Press the button, super learning code can freely learn to match, can be unlimited matching receiver and button. 2.The transmitter without screw chuck design to achieve waterproof and dustproof. 3.The transmitter USE a 23A12V alkaline battery (not included battery). 4.The receiver uses 3 AA alkaline batteries, no need to plug in the power supply, and the battery can be used.(not include battery). 5.Receiving distance:300 meters in open area. 6.The wireless signal will be affected by obstacles. The more obstacles, the more serious the signal loss. 7.Receiver has 4 levels(can be mute) 0-110db,38 music to choose from. 8.Transmitter size:77*51*20mm 9.Receiver size:95*65*24mm 10.The receiver can be hung on the wall or