Pin Spanners
A pin spanner is hand tool that is also known as a 'pin key' or 'pin wrench' and can be both adjustable or with fixed jaws. Pin spanners work by gripping the fastener with pins from the spanner head and attach to the fastener, rather than gripping from the outside of a nut or bolt to turn, like most other spanners do.
An example of where a pin spanner is useful is for loosening or tightening lock nuts on power tools like angle grinders, as well as removing and installing transmission parts, which a mechanic would likely do.
