Silicon Valley firm Knightscope is best known for its K5 security robot: an ovoid tower on wheels that — when it’s not knocking over toddlers or falling into fountains — patrols a few dozen of California’s parking lots and malls. But the company is now introducing two new model to its line-up: the K1 stationary bot and the K7 buggy, pictured above.

Knightscope has been teasing the K7 for a while now, but showed it off in person at a press event this week. The K7 is five feet high and nearly ten feet long, and is designed to patrol grass, gravel, sand, and other tricky terrain. It’s speed is currently limited to 3 mph, but it can go much faster.

Like the K5, it navigates autonomously and has a suite of sensors and cameras that relay audio and video back to a human supervisor. The K1, meanwhile, doesn’t move, but uses millimeter-wave technology to scan for concealed weapons and other metal items. Knightscope says it could be used at hospitals and airports, and is more convenient than a scanner you have to walk through.

You can watch a video of the unveiling below:

Knightscope Unveiled Knightscope Press Conference 10/10/2017 is your last day. Don't Get Left Behind. www.knightscope.com Posted by Knightscope on Wednesday, September 20, 2017

Speaking to The Register, Knightscope CEO William Santana Li said you could think of the company as a “very weird data center.” Thats because its core business, essentially, is managing data inputs from its robots. “The only difference is our servers are outside and they're moving," said Li.

Knightscope hires out its bots to companies for around $7 an hour (although the price for the new K7 is not yet known). That’s half the cost of a human security guard, but Knightscope’s bots offer a pretty limited service by comparison.

They can patrol, detect intruders, and scan license plates, but can’t apprehend someone, and nor can customers program the bots themselves. They’re more like advanced, mobile CCTV cameras, with their technologically-impressive presence acting as an extra deterrent. Just a shame none of the new robots float.