VeriFone added a new wrinkle to its ongoing battle for mobile payment supremacy yesterday, with the announcement of Payware Mobile Enterprise for Tablets -- a peripheral that will allow retailers to process transactions directly from any slate. Much like the company's Payware Mobile system, VeriFone's latest product involves a magnetic card reader and accompanying app that can turn any iPad or Android tablet into a handheld checkout unit. Geared toward larger enterprises, the new device also supports PIN verification for debit cards and NFC payments, rendering it compatible with Google Wallet, though it likely won't see a widespread release until 2012. Perhaps more intriguing is what this move could mean for the company's notoriously heated rivalry with Square. By explicitly targeting bigger retailers, VeriFone seems to be distinguishing itself from the small business-focused Square, despite the fact that its new product looks a lot like one of Jack Dorsey's creations -- or, as some CEOs would call them, "skimming devices."