The phrase "a device that keeps" is correct and usable in written English.
You can use it when describing a device that has the function of maintaining or holding something in place or in a certain state.
Example: "The new gadget is a device that keeps your phone charged while you are on the go."
Alternatives: "a tool that maintains" or "an apparatus that holds".
NASA has built a device that keeps mice floating to study the health effects of spaceflight.
Trucks would also be outfitted with automatic brakes, video cameras and a device that keeps speed below 65 mph.
Decompression unit is a device that keeps the sub-cooled nitrogen by way of the latent heat of evaporation and includes the heat exchanger.
In most cases, it can be treated with a device that keeps a person's airways open during the night using a flow of pressurised air into the throat.
Rule 3, strangely, encourages a sense of alienation: there must be a device that keeps the audience awake and off-kilter by constantly undermining its expectation of a naturalistic world.
Museums often further secure frames with a mending plate, a device that keeps people from moving a picture and prevents it from falling off the wall during an earthquake.
We put in an oral airway" — a plastic device that keeps the mouth open — "he was breathing, and we thought it best to get him to the hospital". "I wish we could have done more for them," she said.
The staff had done a sleep evaluation and supplied her with a masklike device that keeps the user's airways open.
But what about a tiny device that keeps the whole family on their toes by offering a central message pad and shopping list for the whole gang?
It is being sold as a safety device that keeps your phone within easy reach while driving.
Businesses are eager for a wireless device that keeps employees productive while they're stuck in airports or otherwise unable to reach important data.
