You could measure the size of the 5star or you could be a set of the screwdrivrs.Siz
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...
and http://www.8starshop.com/en/12-in-1-comp... I am also sure that there are many more places that have a set of those. Good Luck to you.