STP Brake Fluid Dot 3 Heavy Duty 12 Oz. Case 12STP Brake Fluid DOT 3 Heavy Duty Maximum safety and performance for your brake system STP DOT 3 Heavy Duty Brake Fluid is a high performance hydraulic fluid designed for use in brake and clutch systems that require DOT 3 specifications. Engineered to withstand high temperatures, it helps prevent vapor lock and maintains reliable braking performanceeven under heavy duty or high heat conditions. Manufactured to STPs quality standards, this fluid also