CDL Test Dynamic Prep workbook is intended to help you be more successful on a real CDL written test. If you like to study the test questions with right answers then this product is for you. The information on this book has organized layout included, so you do not have to figure out the approach to learning material on your own, in other words how to start and where to end. This has already been done for you, so relax; learning doesn't have to be painful!The class of the Commercial Driver license refers to the weight of the vehicleClass B--Any single vehicle with GVWR of 26,001 or more pounds, or any such vehicle towing another in excess of 10,000 poundTo obtain the CDL permit class B applicants required to pass the written Knowledge Test as well as Air Brakes endorsement (if applicable)General Knowledge - is a written test (sections 2-4 of your state CDL manual) that covers all of the others in a little detail. It's just to get a basic idea of what the kind of vehicles you may be driving and what different rules you have to follow depending on the vehicle.Air Brakes - is a written test (section 5 of your state CDL manual) that deals strictly with the braking system on heavy vehicles you'll be driving. It informs you on the lack of air pressure in the system during normal driving, which is referred to as brake lag distance. It also deals with the drivers perception distance, reaction distance, which do effect the time it will take to stop loaded vehicle, and what will happen in a skid. What you get: CDL general knowledge test (105 questions/answers organized into three smart practice tests with detailed prep descriptions.) CDL air brakes test (30 questions/answers organized into three smart practice tests with detailed prep descriptions.) CDL Test Dynamic Prep is good for all 50 states