A cell phone booster, a type of bi-directional amplifier (BDA) as commonly named in the wireless telecommunications industry, is a device used to boost the cell phone reception to the local area by the usage of a reception antenna, a signal amplifier and an internal rebroadcast antenna. These are similar to the cellular broadcast towers used to broadcast by the network providers, but are much smaller, usually intended for use by one building. Modern cellular repeater amplifiers work by rebroadcasting cellular signals inside the building. There is a good cell phone booster (www/phonebooster-sk/com) website there. The systems usually use an external, directional antenna to collect the best cellular signal, which is then transmitted to an amplifier unit which amplifies the signal, and retransmits it locally, providing significantly improved signal strength. The more advanced models often also allow multiple cell phones to use the same repeater at the same time, so are suitable for commercial as well as home use. SPECIFICATION SK-GSR GSM Cell Phone Signal Booster Frequency range (MHz) Uplink 890-915 Downlink 935-960 Gain ( dB) Uplink Gp=55 Downlink Gp=60 Amplifying Radius (sq.m.) 30-40m (900-1600M2) Size 148mm×106mm×33mm Weight 5.5KG including all the accessories Function a) Power supply work display b) Export power display Accessory Including: 1pcs Booster; 1pcs Hanging-Carpet-Antenna; 1pcs Inhale-Top-Antenna; 10 meters of cable Port of shipment: Beijing of china, DHL and EMS and UPS, others Delivery time: in 7 days Payment: Credit Card, PayPal Country of origin: China Contact us to send us an inquiry on the SK-GSR GSM Cell Phone Booster. We will get back to you with more details on the same. Signal Knight Brand Cell Phone Booster