Though once used in plumbing, it has since been adapted to crack heads. One of the ends has tape wrapped around it to improve grip, while the other is heavily corroded and/or bloodstained, and topped with a pipe fitting. Though it has a short reach, it has decent damage and a fast swing, making it an especially good melee weapon for players who are just starting out.
It's special V.A.T.S. attack is "Lights Out", which does 125% damage at the cost of 30 action points (requires a Meleeskill of 50).