I am using this formula which works well if I am only trying to match 1 part
number D03KHLL

=SUMproduct(IF(ISNUMBER(A8:A23),IF((YEAR(A8:A23)=2 009)*(B8:B23="D03KHLL"),L8:L23)))

however if I add more part numbers like this

=SUM(IF(ISNUMBER(A8:A23),IF((YEAR(A8:A23)=2009)*(B 8:B23="D03KHLL,D03KJLL,D03KILL"),L8:L23)))

this does not seem to be working they way I have read this to work both in
sum and sumproduct

Any suggestions

Thanks
--
Nelson