1,With two alert modes, vibration and ring. Dormancy function, clock and alarm clock still works but won't receive calls, which can reduce power consumption. 2,Using 3.7V polymer lithium battery, the theoretical standby time is about 20 days. 3,Built-in antenna makes the receiver can receive signal from transmitter directly without the service of base station. 4,It can show 4-digit number or alphabet ​and store 10 call numbers, press the M button to browse the number you need and press the Enter button to call. 5,Maximum 500 storage capacity, the number can be set with multiple combination of alphabet and 0-9 number and the hyphen. (supports 2/3/4 digit call number, such as 01, A1, A-01, ABCD) Receiver Features: 1.With two alert modes, vibration and ring. Dormancy function, clock and alarm clock still works but won't receive calls, which can reduce power consumption. 2.Using 3.7V polymer lithium battery, the theoretical standby time is about 20 days. 3.Built-in antenna makes the receiver can receive signal from transmitter directly without the service of base station. 4.It can show 4-digit number or alphabet and store 10 call numbers, press the M button to browse the number you need and press the Enter button to call. 5.Maximum 500 storage capacity, the number can be set with multiple combination of alphabet and 0-9 number and the hyphen. (supports 2/3/4 digit call number, such as 01, A1, A-01, ABCD) 6.It is widely used in banks, restaurants, hotels, factories, hospitals, offices, leisure clubs, etc. 7.The transmission distance is 1500 meters in open area, and the actual indoor working distance is 100-150 meters. Transmitter Features: 1.Place it on the table or on the wall, press the button and the indicator lights up and send the signal to the receiver. 2.Fashionable and beautiful appearance. Waterproof and easy to change the battery. 3.Mini size and lightweight, convenient to carry and easy to use. 4.Adopts professional communication elements, ensures the stability of signal transmission. 5.World-class coding mode, no messy code. Anti-interference, with built-in timing circuit, ensures fast and safe signal transmission. 6.Anti-temperature and humidity change, can be used in any weather, safe, stable and high reliability. 7.Easy to reset the number, can be reused for multiple purposes. Energy-saving design, long standby and work time. Specification: Quantity: 10 transmitterand1 receiver Model: CTW05andCTT20 Receiver Specification: Receiver model: CTW05 Material: ABS Storage capacity: 500 Prompt mode: vibration, ringtone Power supply: built-in 3.7V lithium battery (needs 5V/1A adapter) Standby: Max. 20 days Receiving frequency: 433.92MHz, 315MHZ Overall dimension: 50 x 15 x 40mm/2 x 0.6 x 1.6inch(size not included watchband), 273 x 22mm/10.7 x 0.8inch(Total length included watchband) Transmitter Specification: Transmitter model: CTT20 Material: ABS Battery: 1pc x 12V battery (not included) Transmission Distance: 300m (open area), 100-150m (indoor) Overall dimension: 60 x 60 x 32mm/2.36 x 2.36 x 1.26inch Frequency: 433.92 MHz / 315 MHz Package list: 1 x Receiver (watch) 10 x Transmitter (button) 1 x Manual 1 x USB cable