Castrol Power 1 4T 15W-50 Engine Oil Castrol Power 1 have been developed with cutting-edge formulation technology, underpinned by more than 100 years' experience in motorcycle lubrication.Castrol Power 1 4T 15W-50 with Power Sustain Technology™ manages heat and friction in bikes, ensuring continuous power delivery through its ability to resist oxidation at higher temperatures.Semi-Synthetic. Specification: API SN; JASO MA-2. 4L Bottle.