A light, low odour anti-wear hydraulic fluid formulated with bio derived and biodegradable esters / vegetable oil; and ferrous and non-ferrous corrosion inhibitors, it does not contain zinc or heavy metals, provides oxidation and corrosion protection plus extreme pressure / anti-wear activity as well as foam resistance. It is recommended for all hydraulic systems when used as an energy transfer medium (heat transfer, contamination removal, sealing and lubrication).