CPR Call Blocker V108 - 1200 Number Capacity - World No.1 - Block Telemarketing Calls Now Worlds #1 Call Blocker - Pre-programmed with 200 rogue calling numbers. The range of CPR Call Blockers work with landline telephony not mobile cellular devices. Block unwanted callers at the touch of a button with the "Block Now" button Block Area Codes, International, Out of Area, Private, Unknown 1200 Number Capacity - Line-powered - Block Calls using cordless Extension handsets by pressing #2 The V108 Call Blocker Does not Currently work with OOMA Phone Lines. NOTE : CALLER ID SERVICE IS REQUIRED FOR THIS PRODUCT TO WORK