Nightstick

A baton or truncheon (also called a cosh, billystick, billy club, nightstick, sap, blackjack, stick) is essentially a club of less than arm's length made of wood, rubber, plastic or metal. They are carried for forced compliance and self-defense by law-enforcement officers, correctional staff, security-industry employees and (less often) military personnel. Other uses for truncheons and batons include crowd control or the dispersal of belligerent or non-compliant people.