Tamper Proof Security Bits 8pc Set T5 T6 T7 T8 T9 T10 T15 Torx Sizes T-5 and T-6 are 6 point star bits commonly used on cell phones and hard drives(no center hole) Sizes T-7,T-8,T-9, T-10 and T-15 are 6 point tamper-proof security bits (with center hole) Heat treated alloy steel, Precision machined sandblasted bits Includes 1/4" hex to 1/4" square drive adapter to fit a cordless drill, nut driver, or ratchet. Includes plastic storage case so the bits you need are always handy