Which one do I need?

Tap what you are doing and the list appears: what you need, what is worth adding, what you can skip, with one line on why. Two optional questions fine-tune it. Every pick is worked out from the products' recorded specifications.

What this does: matches supplies to your situation by their specifications. What it does not do: tell you what to inject or how much; it never asks. If you already know the exact product type you want, the Product Finder goes straight to specifications.