A fleet of five 300-pound, bullet-shaped robot security guards now roam Microsoft’s Silicon Valley campus. The devices, called K5 “autonomous data machines” by their manufacturer, Knightscope, are mostly intended for identifying strange or suspicious behavior, and calling for help if assistance is needed, ExtremeTech reports. They do not carry any offensive weapons, or have any ability to detain humans.

Standing at five-feet tall, the K5 robots boast an impressive array of equipment nonetheless. They come loaded with four high-def cameras, another camera designed to capture car license plates, four microphones, WiFi connectivity, GPS and laser scanning, as well as various other weather sensors, alarms, and sirens.

According to ExtremeTech, the K5’s onboard alarms range from gentle chimes to”ear-piercing” sirens,  which serve to alert and summon a human security guard when one is needed.

“This takes away the monotonous and sometimes dangerous work, and leaves the strategic work to law enforcement or private security, depending on the application,” Knightscope co-founder and vice president of sales and marketing Stacy Stephens told MIT’s Technology Review.

Still, while humans remain a necessary component of the system for now, there is no question that the K5 is intended to replace at least some human functionality. The K5 can run for almost 24 hours on a single battery charge, it can fully recharge in only 15-20 minutes, and it automatically navigates back to the charging point when it’s batteries are low. These abilities make it far more cheaper and efficient than your average human security guard. And as the technology driving the K5’s AI continues to improve in the future, the human security guard may soon be a thing of the past.