Hi there new to the forum but been a browser for a while now. Thought i would let people know just in case like me you were unsure what sizes the wiper blades are on the IS300h. They are 18 Inch 450 MM passenger side and 24 inch 600 mm drivers side. I have just replaced mine with Michelin Hybrid Stealth which have the model numbers MSW12924 drivers MSW12918 passengers for £21.95 on ebay.