Plumber

The Plumber is a travelling handyman who will repair any leakage or breakage as long as the price is right.

Ratchet & Clank
The Plumber is first encountered in the Novalis sewers, fixing a pipe. He gives Ratchet and Clank a 500 bolt Infobot and takes off down the sewer pipe.

They later find him fixing the defence systems on Fort Krontos. The Plumber gives the a Metal Detector for saving the planet and dissapears once again into space.

Ratchet & Clank: Going Commando
The Plumber makes a brief appearence in the pipes of the Aranos Flying Lab, selling a Captain Qwark action figure.

Ratchet & Clank: Up Your Arsenal
On Planet Aquatos, the Plumber is found searching for Amoboid Swamp Crystals in the sewers. He pays Ratchet a decent amount of bolts for finding them.