I've been using Tellus Hydraulic oils for over 20 years in my Machine shop. Initially I went 5 years without changing it and the product was still good according to Oil Analysis. Now I go well beyond that and rely on Oil Analysis to tell me when to change it. Product has yet to fail me.
Was looking for Tellus s2 m68 but Shell is constantly changing their product names but PSC's site guided me right to the correct replacement product. Tx