intent: use 12 variables to get 3 products - 12, or 16, or 24

this formula works

=IF(A4="2 x 6 12 in centers",12,IF(A4="2 x 8 12 in centers",12,
IF(A4="2 x 10 12 in centers",12,IF(A4="2 x 12 12 in centers",12))))

but I have 8 more variables to go ending with ("2 x 12 24 in centers",24)
and the equation is going to be too long.

I tried using the special characters question mark "?" and asterik "*" but
got nowhere.

Any help out there? thank you - Chris, a swell estimator