This is a pair yellow, medium molded foam tire inserts for 40 series monster truck tires from OFNA Racing. These fit all 40 series style monster truck tires such as the Pro-Line 40 series Bow Tie etc. These are an awesome upgrade foam for your tires that will help them maintain the correct shape as well as provide better traction than the stock foams that come with most tires. These foams are also much more durable than regular foam insets, so are not expected to break down as quickly. If the tires wear out quickly due to high traction conditions, save the foams and use them again!
Note: Also check out the orange soft foam insets, if you need a softer foam.