Pick an option under Products to limit search results by measurements types:
"Find files containing any of the selected products" allows you to check grouped products and type in specific product names, requiring all search results to contain at least one of those measurements.
"Find files where all the specific products entered below were measured in the same cruise" requires you to type multiple products in the search bars under "Specific Products," 1 per line (e.g., Rrs and ag). Only relevant files from cruises where all selected measurements were made will be returned. The specific measurements may be found in separate files.
"Don't filter based on products" is the final option, and is also the default behavior if no products are selected.