What is another name for an engine brake?

• A compression brake system
  A truck's engine brake is also known as a compression brake system. Sometimes it's called an engine retarding device. Retarders are especially helpful for truckers on mountain downgrades. How Truck Brakes Work
• A hard-core brake system
  A truck's engine brake is also known as a compression brake system. Sometimes it's called an engine retarding device. Retarders are especially helpful for truckers on mountain downgrades. How Truck Brakes Work
• None of the above
  A truck's engine brake is also known as a compression brake system. Sometimes it's called an engine retarding device. Retarders are especially helpful for truckers on mountain downgrades. How Truck Brakes Work