Lookup and sum on multiple repeating values.

I have tried sorting this out myself but have run aground! Any help is much appreciated.

(I need to do this without removing duplicated or using a pivot table, so I think I need to use sum and lookup in an array form possibly?)


I have two columns. One has a list of product Id's with some repeated values, the other is numeric values.

A B
ProductBall 2
ProductBall 3
ProductGizmo 6
ProductGadget 7
ProductGadget 1

I need a formula that looks up repeated values(product names) in column A and sums the values in column B if column a names are identical. So the above table would yield this:

A B
ProductBall 5. <--- I need solely the formula for this cell.
ProductGizmo 6
ProductGadget 8


Thanks again if anyone has insight!
Tristan