Made for a snug fit on hex-shaped fastener heads, the 6-point opening applies maximum torque without slipping. To prevent round off, it grips the stronger flat sides of heads rather than the weaker corners.
A shallow well and slim walls allow extra clearance for fitting into tight, narrow spaces.
Detent notches inside the drive end securely locks socket onto ratchets and extensions, so it won't fall off or stick on fastener heads.