There's a new type of screw that Apple is putting to its customers. We'd like to call it the iScrew, but the technical name for it is the "pentalobe" or "pentalobular," which is a rounded, five-pronged screw.
While most electronics with tamper-proof screws use the Torx head – which is available for purchase, but not readily available in most households – Apple has gone a step further with something completely new that even DIYers can't get.
The new screw first appeared in the mid-2009 MacBook Pro to prevent battery swaps, and now it's also standard on the new MacBook Air.
The iPhone 4 originally shipped with the Phillips head screws, but now those who have brought their phones into Apple for repair are getting their devices back with the pentalobe screw. Apple's certainly taken additional measures to make sure that customers can't freely open up their own property.
iFixit's posted some additional information and even makes a kit available with screw that will roughly fit the iPhone 4 to swap out for a Phillips.