The phrase "a back up for" is correct and usable in written English.
It can be used when referring to a substitute or alternative option that can be relied upon in case the primary option fails or is unavailable.
Example: "I always keep a back up for my important files on an external hard drive."
Alternatives: "a substitute for" or "an alternative to".
Additionally, the SLS will serve as a back up for commercial and international partner transportation services to the International Space Station," according to a press release from NASA.
Because of more reliability, more fuel flexibility, less environmental pollution, less noise generation and less power fluctuation in comparison with a diesel generator, a microturbine integrated with battery storage is suggested as a back up for this system.
Context would thus make appeals to ubiquitous similarity more plausible, and similarity could be used as a back up for those contexts which fail to produce context-relative identity.
That's the case not just in emerging markets — but, as it turns out, in developed markets, where a feature phone either exists as a "back up" for a smartphone owner, or as a pared-down and smaller device that is simply easier to use.
A recent study conducted by an academic from George Washington University which looked at one group of ISIS supporters' use of mainstream social media suggests Telegram is being favored as a back up for extremists who had been banned from Twitter.
Some primers carried M13 sequences on the 5' end as a back up for sequencing runs.
I said: 'Guitar is just a back-up for your voice.
So expect him to be there, as a back-up for the regular opening batsmen.
Hogarth's house has two pumps going, with a back-up for each in case of failure.
Within any behaviour management system, teachers at the frontline need to use the systems as tools to secure improved behaviour rather than regarding them simply as a back-up for giving sanctions.
Edgeworth FC goalkeeper Jim Fogarty will step up from the NPL for games against Wellington and Melbourne City as a back-up for Jack Duncan, who is already filling in following first-choice gloveman Ben Kennedy's season-ending achilles injury.
