Is "off" also an acronym?

I found the term off used in the following way (technical document):

... a total of two (2 off) Single radio channels ...

While the meaning seems pretty clear, I'd like to know what off stands for in such a context. I supposed it could be an acronym, but could not find any references.

Solution 1:

In this construction, off is redundant in meaning.

It is not an acronym.

It is occasionally used in specifications or ordering, after a number, to indicate that the quantity is of single items, not dozens, pairs, hundreds, etc. By doing this, the format n+multiplier+description is always satisfied, even when the multiplier is 1, so the reader knows that it isn't missing.

I believe it is less common in English now than 40-50 years ago, but is still used in other languages e.g. Swedish stycken (abbr. st.). It may have crept into your technical document as a translation, or by an author being more familiar with usage in another language.

Solution 2:

The OED says (s.v. off, adv., prep., n.1, and adj.:)

12 Used with a preceding numeral to represent a quantity in production or manufacture, or an item or number of items so produced. Usu. as one off: see one-off n. Cf. once-off adj. and n. at once adv., conj., adj., and n. Special uses 2.

with citations from 1934. "Kienzle printers. 6 off, surplus to manufacturing requirements." is an example from 1973