Wireless Calling system advantages:Save labour cost,Improve service image,Most important, improve efficiency How we use the system:First, buttons are pasted or put on wall table, when guest have any service, he she press buttons, receiver (LED screen watch pager) will get signal with vibration sound, showing table number, then waiter know which to be served. Multiple Language receiver:Russian, English, Ukrainian, Spanish, German, French, Italian, could customize your as requiement. 3 Prompts Modes:Vibration, beep, light flash; you can set freely. Call Button Transmitter Specification:Call frequency:433MHz Modulation mode:Ask (Am) Decoding:learning code Working current:17mA Emission Distance:100m (open area) Pager Specification:Capacity: 500 pcs of transmitters Alert Mode: vibration,beep and ring Sensitivity:-110dBm Frequency:433.92MHz Capacity:500 Mode:vibration,ring flash Receive power supply mode:250mAh lithium battery Standby Time:7days (in ideal conditions) Compatible 1, 2, 3, 4, 5 buttons Upgrade function, key value assignment longer time Note: Due different production batches, there may slight differences in products. Specifications: B: orange button Colour:Photo Color Material:Abs Package Contents: 1 x receiver Only above content, other products not included. reflection displays cause color item picture a little from real thing. measurement allowed error is +/- 1-3cm.