Attention: This call blocker is NOT Compatible with Cordless Phones & Two Line Phone systems!! Please make clear about your telephone system, if you have any question, feel free to contact us. ADVANCED TECHNOLOGY This is the only high capacity call blocker available in the market with an LCD display that allows you to block (or blacklist), review and remove up to 1,500 phone numbers at any time.T-Lock / Pro Call Blocker. Block unwanted calls. Stops nuisance callers, potential phone frauds & scams. You can take total control of your incoming calls by manually blacklisting unwanted callers for good. BUY ONE GET ONE OFF PROMOTION Add Call Blocker and Household Ultrasonic Humidifier Machine to cart,Household Ultrasonic Humidifier Machine can save 20%,or add RFID Sleeve to cart,RFID Sleeve can save 10%.Through the button(Add Both To Cart) below. EASY TO SETUP & USE Simply press a button to BLACKLIST numbers forever! Turn ON & OFF feature to Block calls with no caller ID (shown as UNKNOWN, OUT OF AREA, PRIVATE, etc) HIGH CAPACITY Blacklist 1,000 incoming call records by phone number. Block up to 10 incoming area codes. Store/review last 100 incoming call records (add to BLACKLIST when desired). Store/review last 50 outgoing call records (add numbers to BLACKLIST when desired). Block outgoing calls by number prefix (also up to 1,000 call records). Non-volatile memory saves stored data when disconnected from the phoneline. LINE POWERED Requires no external power supplies or batteries. Compatible with FSK/DTMF, PSTN landlines, and VOIP services such as Vonage, MagicJack, Verizon FIOS, Comcast and others.UNIQUE EEPROM - Uses EEPROM technology to prevent losing stored blacklisted numbers when device is disconnected from the telephone line. Package list: 1x Call blocker 1x New Manual 1x telephone line 1x bracket