24/7

or 24-7 or 24X7

[[t]ˈtwɛn tiˌfɔr ˈsɛv ən, -ˌfoʊr-, ˈtwʌn ti-[/t]] sl.

1) sts continually; constantly:

They're together 24/7[/ex]

2) sts continual; constant:

The manufacturer offers 24/7 customer support[/ex]

Also, twen′ty-four` sev′en. Etymology: 1985–90; shortening of twenty-four hours a day, seven days a week