No Crawling Under Tractor/Trailers To Check Proper Brake Adjustment；Removes The Possibility Of Personal Injury Or Damage To Clothing；Eliminates The Possibility Of Not Detecting Brakes Out Of Adjustment Leading To Fines,Premature Brake Wear Or Decreased Braking Ability；Helps Prevent Contaminates From Entering Brake Chamber Potentially Limiting Brake Effectiveness While Extending Brake Chamber Life；In Some Countries Brake Stroke Indicators Are Mandatory On All Air Brake Equipped Vehicles Including Tractors, Trailers And Buses. The Vehicle Will Be Rejected If The Brake Push Rod Stroke Indicators Are Missing Or Showing Overstroke Condition