Mixed metaphor accid / Mixed metaphor accid

OPW nozzle design prevents oils to be mixed up.
Oils are mixed often when people fail to distinguish
if thecar runs on disel fuel or gasoline. The OPW
nozzle and oil hole is designed as in a same shapeso
that it could not cause an injection mistake.
Furthermore, the design allows a user to check the
capacity and control with electronic panel on upper
part of OPW nozzle