Features: 433 MHz frequency, wireless transmission is more than or equal to 200meters in open place. Low-consumption design, which can make it work long-time. Our nurse caregivers SOS-call button system for patient, disabled, elderly and children is simple to use and provides peace of mind. Suitable for use as an aid for elderly, pregnant woman, children or disabled who can not stand up from toilet, bathroom fainting, floor mat fall alarm or heart-attack, calls for help. Simply press call button to the caregivers via the receiver or wireless alarm host. Widely used in home, hotel, hospital, retirement home and other needed places. Call button can be wall mounted on bedside, sofa, closestool or placed near caregivers. Specifications: RF-frequency: 433 MHz Modulation mode: ASK (AM) Working chip: learning code Power supply: 3V CR-2032 button batteries (included) Working current: 17mA Launching distance: 200m (open area) Operating temperature: - 20 ℃ to 55 ℃ Size:Approx.6.4x6.1x1.5cm/2.52''x2.40''x0.59'' Quantity:1Pc,2Pcs,4Pcs(optional) Package Includes: 1x Wireless Pager or 2x Wireless Pagers or 4x Wireless Pagers note: Please allow 1mm errors due to manual measurement. Due to the difference between different monitors, the picture may not reflect the actual color of the item.