AP Radi-CAL R3 far exceeds DOT 4 specifications. It has been formulated and refined specifically for racing use where very high temperatures cause other fluids to boil. R3 is less viscous than standard fluids to make bleeding easier. Improved moisture resistance reduces the rate of water absorbtion, and a new corrosion inhibitor (not present in AP PRF fluid) makes R3 compatible with magnesium components.
To ensure that the fluid stays fresh during shipment, AP brake fluids are furnished in 1/2 liter (16.9 oz), easy-pour plastic bottles with double-sealed caps. Bottles should always be tightly resealed to keep moisture out.