These boxes are open on one end and measure 1 3/8" x 1 3/8" x 3". They come with white or red end caps which fits securely over the open ends. The end cap once set in place is difficult to remove. This will protect the car inside from being damaged by rubbing against any surface which could cause it damage. These boxes are very durable and can be used over and over again. They have been designed to replicate the original Tuff-Ones boxes very closely. They are probably just a bit thicker in both the tube as well as the end caps. Protect those valuable cars and other items that might fit.