<Tr> <Th> Available </Th> <Td> In use </Td> </Tr> <Tr> <Td_colspan="2"> Notes Tamper resistant screw </Td> </Tr> <P> The Pentalobe security screw (Apple nomenclature), or pentalobe screw drive, is a five - pointed tamper - resistant system used by, among other companies, Apple in its products . Pentalobe screws were adopted by Apple starting in 2009, when they were first implemented in the 15 - inch MacBook Pro . They have since been used on other MacBook Pro, MacBook Air and iPhone models . Apple attracted criticism upon the introduction of the pentalobe screw; it was seen by some as an attempt to lock individuals out of their devices . Inexpensive pentalobe screwdrivers, manufactured by third parties, are relatively easy to obtain . </P> <P> Pentalobe screw sizes include TS1 (0.8 mm, used on every iPhone after and including the iPhone 4), TS4 (1.2 mm, used on the MacBook Air and the MacBook Pro with Retina display), and TS5 (1.5 mm, used on the 2009 MacBook Pro battery). The TS designation is ambiguous as it is also used for the Torq - set screw drive . </P>

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