COMPATIBILITY: Works with most traditional analog landline phones and services from providers like AT&T, Verizon, Frontier, CenturyLink, and Brightspeed. NOT COMPATIBLE with internet-based or digital phone services (VoIP), including Vonage, Ooma, Xfinity Voice, and Quantum Fiber. CALLER ID REQUIRED: The V100K requires Caller ID service to identify incoming numbers. Without it, calls cannot be blocked automatically. No external power supply is needed - simply plug into your phone line and start using it. EASY MANUAL BLOCKING: Preloaded with 100,000 known nuisance numbers and allows instant blocking of new or repeat numbers using the large “BLOCK NOW” button. You can add up to 10,000 additional numbers, giving you control over unwanted calls. REALISTIC CALL PREVENTION: While no device can stop 100% of spam or spoofed numbers, the V100K helps shut down repeat offenders quickly and gives you more control than passive filters alone. SIMPLE DESIGN: No power supply, app, or subscriptions required. Clear display, tactile button, and simple installation make it easy for seniors or anyone to use. For extra protection, pair it with your phone provider’s spam filtering service. SUPPORT & WARRANTY: Every unit comes with a 3-year manufacturer warranty and lifetime customer support. Contact details are included in the box for personalized assistance whenever you need it. Call Blocker for Landline Phones - Say no more to robocalls, spoof calls,political calls, scam calls, unwanted calls, nuisance calls, telemarketing calls: block all at the touch of a button! The CPR V100K Call Blocker features a 3 inch caller display screen, large "Block Now" Button, 110,000 Number capacity and has the ability to block unwanted callers from cordless DECT extension handsets by pressing #2. V100K Main Features: Easy to use controls: With CPR Call Blocker easy to use control buttons you can view the callers number on its large 3 inch display and view the blocked number list as well as see how many times that blocked number has tried to recall. If required blocked numbers can be easily removed from the block list using the delete button. Built in Number List: The CPR Call Blocker is pre-programmed with more than 100,000 numbers which are 'deemed' As known nuisance callers. Companies which are selling by phone, using overseas call centers and automated sales lists are all pre-programmed which will minimize the sales calls you receive almost immediately. Block Now function: The ‘Block Now’ button is located on the top of the unit. At the touch of a button the unwanted caller’s number is logged into the unit’s memory, the call will hang up and the number blocked Permanently. This feature allows you to block up to 10,000 unwanted callers as they are calling you. #2 Blocking function: Block a number by entering #2 on any DECT handset connected to the telephone base. Manual entry: Manually enter or remove numbers to/from the blocking list Compatibility: Compatible will all major US line providers including AT&T, Comcast, Coma, Verizon, Century Link, Frontier etc. Caller ID services from your network provider is required for this product to work.