A small submersible pump. They have only one moving part, called the impeller. They are useful to create current within a tank or to drive filters such as under gravel filters, canisters and protein skimmers.

A water pump designed for water circulation or movement. Also used to pump water between tanks or devices.

A power head is a small, submersible pump which is used to power wavemakers and UGF's (undergravel filters).

The terms powerhead, bang stick, and shark stick refer to specialized firearms intended to be used underwater and fire in direct contact with the target. These are often used for spear fishing, or they may be used against sharks or alligators for sport, defense, or to kill nuisance animals. The term powerhead generally refers to just the firearm-like part of the device; when attached to a shaft to form a spear, they may be referred to as a bang stick or, if intended for defense against shark attacks, a shark stick.

a very short barreled gun