Compatible with modern transformers that demand a very high technical oil standard as well as the ageing infrastructure that original equipment manufacturers and utility companies use, the Shell Diala S4 ZX-I is used to fill tens of thousands of transformers today in India, China, Korea and many European countries. As compared to products derived from crude oil’s varying quality, its gas-to-liquid (GTL) base guarantees a globally consistent product. GTL also gives it a higher lightning impulse breakdown than conventional oils and makes it free of crude oil-based impurities. The Diala S4 ZX-I’s cooling benefits from three factors: high specific heat capacity, high thermal capacity values, and its good fluidity and flow properties at low temperatures. Further, its excellent flashpoint gives it endurance in strenuous operating conditions. The inhibitor-infused oil is far more oxidation-resistant than crude oil alternatives. A Shell study has also confirmed that the Diala S4 ZX-I works well in combination with conventional oils. By helping reduce extra filtration handling, oil replacement, downtime losses and earlier replacement of the asset than anticipated, the Diala S4 ZX-I is more cost efficient than its competitors. Since its launch, over 100 million litres of the oil has been sold.