PRINEVILLE, Ore. -

 From a shelter pup to a hearing dog, Ruben is Kathy Zierlein's new best friend.

"He's no different than having a normal dog. He just has an extra job," said Zierlein.

On the clock 24 hours a day, Ruben gets paid in treats. the Prineville woman relies on reading lips and hearing aids to get through her day But at night, the aids can get uncomfortable.

"So to be able to take those out and have a break from that, but know that you still have 'ears' that are working for you" is a big help, said Emily Minah, a spokeswoman for Dogs for the Deaf.

Ruben is trained to lightly jump on Zierlein if he hears someone at the door, the phone ring, or in more extreme cases, the smoke alarm go off.

While we cringe at the sound of our alarm in the morning, Zierlein gets can't hear it without her hearing aids.

"He lets me know when the alarm goes off. That's really important for work because I have to be on time," she said.

Ruben is Zierlein's second hearing dog; it's been five years since her first passed away.  As with all new relationships, it'll take some time before the two are perfectly in sync.

"I just have to remind myself to be patient and let him be, but at the same time remind him what he's supposed to do," said Zierlein.

Minah says the bond was instant.

"I can be sitting right there, and he knows me, but Kathy leaves and he's starting to act like, 'Hey, where's my mom?' So he's already starting to know who his person is," said Minah.

With alert ears and a big heart, Ruben is much more than just a pet. He's a life changer.

Dogs for the Deaf relies on outside donors to support rescuing the dogs and training them. Zierlein's new hearing companion was sponsored by the Sammamish Sam's Good Sam Club.