A Chainlock, also known as a smiley is an improvised weapon

Weapon

A weapon, arm, or armament is a tool or instrument used with the aim of causing damage or harm to living beings or artificial structures or systems...

 which consists of a length of chain

Chain

A chain is a sequence of connected links.Chain may also refer to:Chain may refer to:* Necklace - a jewelry which is worn around the neck* Mail , a type of armor made of interlocking chain links...

 or strong cloth attached to a large lock

Lock (device)

A lock is a mechanical or electronic fastening device that is released by a physical object or secret information , or combination of more than one of these....

 or other piece of metal. The Chainlock is mainly used in areas where other hand held weapons are not readily available, such as knives

Knife

A knife is a cutting tool with an exposed cutting edge or blade, hand-held or otherwise, with or without a handle. Knives were used at least two-and-a-half million years ago, as evidenced by the Oldowan tools...

.

The Chainlock is used by swinging the heavy end of the chain

Chain

A chain is a sequence of connected links.Chain may also refer to:Chain may refer to:* Necklace - a jewelry which is worn around the neck* Mail , a type of armor made of interlocking chain links...

at the target. The Chainlock is not usually considered to be a lethal weapon, but can cause a lot of damage when used correctly.

It is normally used in gang warfare.