【IP44 Waterproofing】: The transmitter is splash-proof (equivalent to IP44 waterproof standard), offering excellent waterproof and dustproof performance, allowing use outdoors or in the bathroom without worry, even on rainy days. However, avoid submerging it in water or using it in areas where it will be directly exposed to rain. 【Stable Transmission】: This doorbell can transmit wirelessly up to 300 meters (manufacturer's specification) in an unobstructed area. The high-sensitivity receiver can stably receive signals through walls, wooden doors, steel doors, etc., and can be used in two-story buildings. Installation is easy without any construction. 【Volume Adjustment & 36 Melodies】: The doorbell has a loud calling sound with 4 adjustable volume levels, ranging from 0dB to 100dB. 36 melodies are selectable, satisfying a variety of environments and needs. It is also recommended for those with hearing difficulties due to its loud volume. 【Easy Installation】: This entrance chime requires no wiring. The doorbell receiver is battery-powered, and you can fix the transmitter to the door frame (adhesive tape is possible) and the chime will play when the button is pressed. Installation is easy without any construction, making it very convenient. It can be used by children and the elderly. 【Wide Range of Applications】: Can be used for home security, restaurants, offices, hotels, and nursing care facilities. It can be used in various environments. In addition, it is useful for calling at the entrance, reception, dining, and for visitors, as well as for those who need assistance in izakayas (Japanese pubs), and it is applicable to various scenarios.