NOT TO BRAG, WE ARE THE BEST SLYNUMBER is not just another second number app. SLYNUMBER is the ONLY provider on the market to offer real mobile numbers. We don't provide VoIP, fake phone numbers, or second lines that only work for a week. This distinction is crucial because many apps and online services do not accept VoIP numbers. SLYNUMBER works everywhere! To put is simply - unless you're willing to sign up with a major carrier like T-Mobile, Verizon, or AT&T and commit to an expensive plan ...