Rain-X

Rain-X invented the consumer windshield water repellent category in the late 1960s and has maintained dominant brand recognition ever since. The product is made by ITW Global Brands, a division of Illinois Tool Works (ITW), and is available in virtually every auto parts store, Walmart, and Amazon in the United States.

The brand's core product — a pump-spray silicone/siloxane treatment applied to exterior glass — is the reference benchmark against which all competing rain repellents are compared in the detailing community. The "up to 1 year" label durability claim is widely criticized by real-world users who consistently report 4–8 weeks on daily drivers. Despite this gap, the product's highway sheeting performance remains among the best in the category. The 2025 SDS reformulation introduced ethanol as the primary carrier, replacing the older isopropyl alcohol formula, and added a carcinogenicity classification (H350, California Prop 65) that is not reflected in older SDS versions.