【IP44 Waterproof】: The transmitter is splash-proof (equivalent to IP44 waterproof standard), so it has excellent waterproof and dustproof performance and can be used outdoors or in the bathroom, even on rainy days. However, please avoid using it submerged in water or in places where it is directly exposed to rain. 【Stable Transmission】: This calling chime can transmit wirelessly up to 300 meters (manufacturer's specification) in an unobstructed area. With a high-sensitivity receiver, it can receive signals stably through walls, wooden doors, steel doors, etc., and can be used in two-story buildings. Installation is easy without any construction work. 【Volume Adjustment & 36 Songs to Choose From】: With a loud calling sound, the volume can be adjusted in 4 levels, with a variable range of 0dB to 100dB. 36 songs are selectable, satisfying a wide variety of environments and requirements. Recommended for those with hearing difficulties due to the loud volume. 【Easy Installation】: This doorbell requires no wiring. The doorbell receiver is battery-powered, and you can simply fix the transmitter to the door frame (adhesive tape is possible) and press the button to play the chime. It can be installed without any construction work, making it very easy to use. Children and the elderly can also use it. 【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 for the entrance, reception, meals, visitors, etc., and also for those who need assistance in izakayas (Japanese pubs), and it is applicable to various scene needs.