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Practice quizzes / Wisconsin CDL Air Brakes Practice Questions - Wisconsin CDL Air Brakes Knowledge Test Exam / Question 204833
Practice question

For Wisconsin CDL air-brake testing, what is the shape and color of the trailer air supply control on a tractor?

  1. A yellow diamond knob
  2. A red 8-sided (octagonal) knob
  3. A blue triangular knob
  4. A green round knob

Answer: B — A red 8-sided (octagonal) knob

The correct answer is shown above. Try the full quiz for additional practice.

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