As to standard barrier ac hose and reduced barrier ac hose, the inner diameter is same, the different is the outer diameter. Standard barrier ac hose has a bigger outer diameter than reduced barrier ac hose.

Resistance to Leakage: Look for hoses that have good sealing properties and minimize the risk of refrigerant leakage. This helps maintain the efficiency and performance of your air conditioning system.

The power steering hose on a BMW E38 is an essential component that helps to transmit power steering fluid throughout the system, allowing for smooth and easy steering. This hose is responsible for carrying the pressurized fluid from the power steering pump to the steering gear, ensuring that the steering wheel can be turned with minimal effort.