Product advantages: Self-generation without batteries: electromagnetic motion self-generation technology eliminates the trouble of replacing batteries, energy-saving and environmentally friendly, making life more convenient. Super waterproof: Not afraid of wind and rain, IP44 waterproof capability, no water leakage, no fear of strong wind and rain Better signal, strong penetration: 3rd generation upgraded more advanced A7 signal processor, super strong induction antenna Open measured distance of 150 meters, digital signal circuit is more to interference Superheterodyne wireless technology: compress the wireless signal, increase it, and then force it to amplify it Greatly enhance the signal propagation distance, making it farther 4-level volume adjustment: high volume, low volume, silent, medium volume Plug Type:EU Plug,it applies to Indonesia, Germany, France, Spain, Italy and so on Voltage: AC100-240V Color: White Material: plastic Package Contents: 1 x Doorbell 1 x Ding machine 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.