First-fill basics
Choosing a technical fluid is not a taste question — somewhere in your service book, or on the reservoir cap itself, a designation is already printed. These six field rules turn it into the right can.
A viscosity grade like 5W-30 describes flow, not fitness: two 5W-30s can carry entirely different approvals. Find the specification your handbook names, then the can that answers it — always in that order.
European hydraulic reservoirs are the easy case — the cap often says CHF 11S in so many words. That sentence ends the search.
Between services, a system drinks the fluid it holds. The one-litre cans exist for that; for hydraulics, Pentofluid EHF is label-approved to mix with CHF 11S and CHF 202, so a low reservoir is a correction, not a flush.
Five litres is a drain-and-fill; one litre is the trunk can. Buying the jug for a service and the litre of the same fluid for the glovebox covers a year of ownership in two line items.
Every product page here leads with the Pentosin part number; your dealer's parts desk can confirm a designation from the VIN in a minute. If a listing here ever disagrees with your handbook, the handbook wins — tell contact@pentosin.org and we fix the listing.