Indeed, but unlike yours it also works for eg C-18,C-27,C-334,C-21.

**@Andrew**
Ah, the commas... I forgot about them!

**@TheAssetMgr**
As Andrew pointed out in Message #8, my formula, as written, could fail if you had three or more digits after the dash. Here is my corrected formula (I also removed the unnecessary >0 from my formula (Andrew's formula reminded me that is was unnecessary as well)...

=IF(SUM(0+ISNUMBER(FIND({"C-32,","C-33,","C-34,","C-35,"},A1&",")))>0,"","Error")

If you look carefully, you will see if we change the SUMPRODUCT to SUM (as mentioned in prior messages) and note the remaining differences are Andrew's "--" instead of my "0+" (two different ways to accomplish the same thing... in this case, to convert Boolean values to real numbers so they can be added, but the same "trick" can be used on text that looks like numbers in order to convert them from text to real numbers) and Andrew's use of SEARCH (allows the search to be case insensitive) as opposed to my use of FIND (which makes the search case sensitive), our formulas are identically constructed. The real difference between them whether your "C" characters will always be upper case or not, so use whichever applies to your circumstance.