These block train capsules are a fun project for your party or event. After the trains are built. They roll freely and are able to be stored in their capsules. These make a great party favor for the guests also. Each Capsule has a surprise train block kit that can be built two ways. These blocks are also compatible with other block manufacturers. There are four different styles/colors. Sorry no color choice is available. Each capsule is 3" tall x 2.5" wide.