The super-rich take security very seriously, and they're willing to spend a fortune to feel safe. In some cases, that means investing in highly trained super-dogs that cost more than a house. With a single command, these four-legged bodyguards can go from cute and cuddly to a bad guy's worst nightmare. The price of this unique protection can be as much as $230,000. "Our clients range from executives, to professional athletes and lots of women who are home alone quite a bit," says November Holley, president of Harrison K-9, an Aiken, South Carolina-based company that imports and sells "executive protection dogs," as she refers to them. The pricey breed is called the European German Shepherd, and they are bred and certified in Germany to optimize guarding skills. In fact, it's the breed commonly used in law enforcement. After about two years of daily training in Germany, Harrison K-9 imports the elite guard dogs to the U.S. The company hand-selects each pooch for obedience, the ability to track scents, response to on-command attack cues and more. The animals then receive six to 12 more months of rigorous training on the ground in Aiken.

Harrison K-9 President November Holley. Source: Harrison K-9

The company trains the dogs to be trilingual, so they can instantly respond to commands delivered in English, German and by hand signal. It is a communication skill set that can take years to develop, and it's required before a dog can be placed in a client's home.

A Harrison K-9 trainer works with an executive protection dog. Source: Harrison K-9

The price of a fully-trained protection dog ranges between $30,000 and $80,000, with the average sale price around $50,000 says Holley.

A ferocious looking black and tan European German Shepherd named Robbie is priced at $60,000 Source: Harrison K-9

But that price can go much higher if the dog comes from a pedigreed bloodline, or is an award winner. "The most expensive dog we ever sold was for $230,000, and she was named Julia," Holley tells CNBC. "There's a show in Europe, you can equate it to the Miss Universe pageant. [Julia] placed in the top 50 dogs in the world."

Harrison K-9's most expensive dog ever sold, Julia, who's purchase price was $230,000. Source: Harrison K-9

In 2018, Harrison K-9 sold 50 executive protection dogs. Holley says so far this year she's already sold 30, with seven more dogs likely to sell by the end of this month. Holley says the company is also seeing demand grow outside of the U.S. This year alone, six of her dogs have gone to families in Mexico.

Hardy ($47,000) and Happy ($42,000) two Harrison K-9 dogs headed to Guadalajara, Mexico to protect a wealthy family. Source: Harrison K-9

Holley tells CNBC clients utilize these dogs as another "layer" of home security. For instance, if a video monitoring system cannot surveil every corner of an estate, the protection dogs can fill the gaps. "A bad guy, he can hide from the video camera and you won't see him, but the dog — he'll know right away and get him," says Holley. "The dog isn't going to be fooled."

A trainer being chased during an exercise with a Harrsion K-9 protection dog. Source: Harrison K-9

"It was an investment of security and safety, peace of mind to me that is priceless" says Harrison K-9's long-time client Sandy Bentley. Over the years she's spent north of $300,000 on six dogs.

Bentley in a private jet with her protection canine Valdemar. Source: Sandy Bentley

The former Playboy cover model and ex-girlfriend of Hugh Hefner says there were moments when she would feel unsafe as a model living in California: "I was weirded out. Creepy guys recognized me, and I didn't want anything to happen …instead of an alarm system, I got a portable security system I could take with me." Her current bodyguard and best friend is an all-black protection dog named Valdemar. "Their breeding and temperament is so stable, you can literally put them in any environment," even on the private jets she and her fiancé use to travel, Bentley says. "They are more intuitive than any dog, you just don't have to worry."

Harrison K-9 client Bentley with her security dog. Source: Sandy Bentley

In some cases, Holley tells CNBC, customers turn to security dogs as a replacement for human bodyguards because a dog's loyalty is unquestionable. "The bodyguard still has self-preservation to think about, but the dog's sole focus is only you." Many times, new clients are spurred to purchase a protection dog after a family member becomes the victim of a crime. Michelle Wilson Gall is a prime example. At 16, she fell victim to a car-jacking in Los Angeles; after the scary crime, her dad bought her a protection dog. Gall has since gone on to purchase two security dogs herself from Harrison K-9 and she credits her latest pup, named Scarlet, with saving her life after nearly being assaulted in an elevator.

Scarlet in the passenger seat of Gall's all-terrain vehicle. Source: Michelle Wilson Gall

"Scarlet sensed my fear pheromone. [The assailant] kept coming toward me, and immediately she grabbed him and just kept shaking." Gall says Scarlet is trained to bite and latch on to the assailant's arm and not let go until she gives the command. "I gave her the 'let go' command when we got to our floor and ran out; the cops later got him," Gall tells CNBC.

Gall's security canines Scarlet and Nero. Source: Michelle Wilson Gall