Bits have a different size at each end. An opening at the tips accommodates the pin in the recess of tamper-resistant Torx screws. These are also known as pin-in-Torx bits.

An opening at the tip accommodates the pin in the recess of tamper-resistant hex screws. These are also known as pin-in-hex or pin-in-socket bits.

Grip the indentations on the head of tri-groove fasteners.

An opening at the tip accommodates the pin in the recess of tamper-resistant square screws.

These are also known as known as butterfly and Type G bits.

Ribs forged into the wings of these offset-cross-shaped bits grip the screw recess to reduce stripping. They are also known as ACR® bits.

Less likely to crack or shatter under high torque than standard bits, these are often used with power tools to install machine screws.

An opening at the tip accommodates the pin in the recess of tamper-resistant hex screws. These are also known as pin-in-hex or pin-in-socket bits.

These bits have an offset cross shape.

A three-winged tip fits triangular slotted screw recesses.