I have a spreadsheet that will constantly updated by customers. I want to
create a formula to automatically summarize a list of various components. For
example:

Column A Column B
Material 1 Thickness 1
Material 1 Thickness 2
Material 2 Thickness 1
Material 1 Thickness 1

I want a formula on the spreadsheet to summarize this data so that it will
produce a list as follows:

Column A Column B
Material 1 Thickness 1
Material 1 Thickness 2
Material 2 Thickness 1

Many thanks in advance!