Billy clubs are hand held sticks varying in length but are usually no more than a yard long. It is like a thinner and shorter version of a baseball bat.
They are also called batons, truncheons or nightsticks. They are defensive weapons basically used by policemen as part of their law enforcement equipment.
A billy club or baton is basically a striking instrument and can be a source of intimidation. Just the mere thought of being struck by a billy club would make many people think twice about advancing forward. It can be used to control crowds or subdue an unruly individual.
The billy club is a piece of versatile equipment as it can also be used in situations like breaking a car windshield to reach trapped people or breaking windows or doors in other emergency situations.