Pro Call Blocker CT-CID803 Plus helps stop nuisance and unwanted telemarketing calls with a single button. This landline device features an FSK/DTMF dual system and a large memory capacity capable of storing up to 4000 numbers in its blacklist. The unit includes a clear LCD screen with 5 adjustable brightness levels, allowing you to easily review and delete incoming call history or manage your white and blacklists. Compact and easy to install, it connects directly to your existing phone line to provide immediate protection against robocalls and scammers. Includes user manual and phone cord.