Prime Guards Brake Fluid - Dot 4 is compatible with any brake or hydraulic clutch system running Polyethylene Glycol (polyglycolic) DOT 3, DOT 4, and DOT 5.1. It's perfect for Drum and Disk brakes. Excellent braking response due to high boiling point of fluid. High wet boiling point ensures long term retention of fluid performance. Better performance for life of fluid compared to DOT 3 fluids Prime Guards Brake Fluid - Dot 4 is compatible with any brake or hydraulic clutch system running Polyethylene Glycol (polyglycolic) DOT 3, DOT 4, and DOT 5.1. Its high boiling point of fluid creates an excellent braking response, and its high wet boiling point ensures the long-term retention of fluid performance. Prime Guards Brake Fluid “ Dot 4 is perfect for Drum and Disk brakes.