Protect-O-Bot

The Protect-0-Bot is a special type of protectron which was never mass-produced by RobCo. It can be seen in Fallout: New Vegas at the REPCONN Headquarters in a state of disrepair, as an exhibit in a museum.

Background
Excerpt from the description in the REPCONN's museum:

 "Some folks have asked - why not a Protectron with wheels? RobCo wasn't afraid to answer that question: The Protect-0-Bot is the answer. While safety standards prevented this free-wheeling dynamo from entering mass market production despite RobCo's best intentions and teams of lawyers, we take the consolation in letting you can see this extremely well-funded experiment as it was intended - a robot moving so fast it looks like it's standing still!

Exhibit Brought to You By Your Friends at RobCo"

It's a protectron with a car-type design, wheels rather than normal legs and with a dynamo accelerator. It looks a lot like the torso and head of a regular protectron with the wheels and legs of a sentry bot.

Locations

 * Found in the museum of REPCONN Headquarters.