Sentry Bot

Sentry bot is a robot that appears in Fallout 3 and Fallout: New Vegas.

Background
 Sentry bots (military serial numbers SB-XXXX) are security robots made before the Great War with the express purpose of participating in the heaviest of firefights during war. Where the Mister Gutsy is a hovering platform with modest armour plating and the protectron a push over, the sentry bot is a powerhouse, equipped with a sturdy armour plating, powerful weapons integrated into its chassis, and benefits from high mobility thanks to wheels mounted on its three legs.