I have an issue here.
I have a huge listed of assets - the column i where my info is has vasrious serial numbers.... some are a simple string of letters/numbers and the others look like this for example AG-1234567

I need to somehow pull out the ones that look like that. (AG-1234567). I only need those. Now normally i would just do a filter and pull em out however, this sheet contains 73k worth of items.

what would be the formula to perform such a task?

please help!