TRD Radiator Cap 1.3 BAR (07-23 Tacoma/07-21 Tundra/07-23 4Runner)This Toyota TRD Radiator cap is designed to release at higher cooling system pressures than factory caps, raising the coolant boiling point to protect engines under high rpm or high load operation Helps enhance vehicle performance in high rpm or high load conditions Designed to release at higher cooling system pressures than factory caps, raising the coolant boiling point to protect engines under high rpm or high load operation