Here's one approach:
1) Define a range containing your types of products (say "Type")
2) For each "Type" define a range with the list  of products
3) In any cell (say A1 for your box  1)use Data Validation to create
a drop down of the types by selecting list and putting "=Type"
in the source box.
4) In another cell (Say A2 for your box 2) use Data Validation,
select list, and put "=INDIRECT(A1)" in the source box.
When the user selects a product type  in A1, the drop down in A2 will
contain the list of products for that type.