US Postal Service Truck. The wheels are free-rolling and made of rubber. Moreover, the back wheels have pull back action, which means that it will wind up when you pull it back and it will roll if you let it go. The doors can open revealing interior details such as seats, steering wheel, and instrument panel. The rear gate opens up too. These toy models are great for children and adults. Collect them or play with them, as they pull back and go! - Happy Cheese Kings Official Authentic items.