SINGCALL Wireless Calling System, Double-button Pager,5 Pagers and 1 Pc Watch Receiver Need more watch receiver? Please search B00EC6P0K8 on Amazon. APE6600: 01.Directly receive signals of pager(s), convenient to take. Show the time when on standby mode. 02.With sleep mode, saving power and avoid disturbing when do not use. 03.Two prompt modes of vibration or beep, the length of vibration can be set from 1-5 seconds. 04.'Lock the watch' function, can aviod misoperation. 05.Frequently Asked Questions attached in the last page of manual, can solve most problems. APE 620: 01.Double-button pager 02.Stable Login Mode 03.Anti-temperature and humidity changes 04.The number can be changed optionally with strong re-use ability Specifications:2.17*1.77*0.6 inches(55*45*18mm) Us Frequency Range:433MHZ Sound Type:Music/Vibration Standby Time:30 days long With Pager Quantity:999PCS Receiver Sensitivity:-114dbm Power Supply:AAA battery Call output: 20db UV/m Us Frequency Range: 433MHZ Frequency deviation: 0.5 Mhz Specifications: 2.36*2.36*0.71 inches(60*60*18mm) Call distance: 130-200ft indoors, 1600ft in the open air Power Supply: Alkaline Battery 12V 23A