http://shop.ebay.co.uk/merchant/nicktheskid

Just for future reference, you need to swap "off" for "of", for example "3 of 90 degree..." rather than "3 off 90 degree..."

I know its picky but little grammatical errors really annoy me, plus well written descriptions will sell better on ebay.

In the engineering world, 3 of something would be referred to as 3 off not 3 of.

Nick is right.

I agree 3 off is correct.

It seems odd, but I agree that "3 off" is the usual expression

I'm always happy to stand corrected - every day is a school day.

However I was sure I was right to express these as 'off'.

I'm sure in any expression of quantity the word 'off' is used to avoid it being confused with a dimension if 'X' were to be used.

Perhaps 'off' comes from 'off' the shelf or 'off' the stock inventory.

Anyway listing more stuff tonight so save yer pocket money!!

I believe it comes from a simular term as off cut.
ie,
I have a 3 metre spar of wood. Please cut off 4 60 cms lenghs... 4 off 60cms

Or if you think of a custom made item, you would refer to it as a 'one off' not 'one of'