You could measure the size of the 5star or you could be a set of the screwdrivrs.Size Inch point to point [in] Metric point to point [mm]
T1 .031 .81
T2 .036 .93
T10 .107 2.74
T15 .128 3.27
T20 .151 3.86
Looks like very limited availability :) http://www.traderscity.com/board/product...-1/offers-to-sell-and-export-1/offer-zhida-brand-star-bit-tamper-torx-bits-security-bit-5-point-star-6point-torx-95182/
and http://www.8starshop.com/en/12-in-1-computer-phone-tool-repair-screw-drivers-set.html I am also sure that there are many more places that have a set of those. Good Luck to you.