The phrase "a handy device for" is correct and usable in written English.
It can be used to describe an object or tool that is convenient or useful for a specific purpose or task.
Example: "This app is a handy device for organizing your daily schedule and reminders."
Alternatives: "a useful tool for" or "a convenient solution for".
Kodak suggests a handy device for keeping this all straight.
A handy device for any outdoor enthusiast, the Rugged Rukus, which comes in green or black, is available at Amazon.com and Apple and REI stores for $100.
Typing (and therefore emailing) on the Nexus 7 is easy even when the device is in portrait mode, which makes it a handy device for commuters.
That makes it a handy device for spotting turning-points in economic confidence, with the added advantage that the data are available earlier than for conventional survey-based figures.
It thus appears to be a handy device for filling out digital forms, which is one reason why Microsoft recently unveiled XDocs, a new piece in its software suite, Office.
Or might the Shake Shack Cam turn out to be a handy device for spotting a criminal, turning up any moment on CSI? ("Hey, boss— there behind the Senator Roscoe Conkling Monument — isn't that a man stabbing someone repeatedly? No, forget it, he was just shaking ketchup on his 'Shroom burger").
But his position that both sides will able to "express reservations" (a handy device, some argue, for assuaging domestic opposition) threatens to undermine his own work.
It was also the world debut of the computer mouse, an idea driven by Engelbart's own desire for a handy device to interact with his computer screen.
The Knee Defender, a handy device that halts the ability for an airplane seat to recline, gained Internet fame in June.
Drawing on the advances made by the military, commercial electronics companies began experimenting with more anodyne applications, ushering in the age when remote control became a handy device intended to make life easier for consumers.
