Enjoy hours of play when you set up your HO scale trains using this Atlas metal rail joiner set. These track connectors work with the two-rail system of tracks and DC power supplies. They are made of gray plastic and easily snap into place. When you want to reconfigure the track, the connectors can be removed with the push of a finger. These connectors come in a pack of 48, and they are designed for people ages 14 and older.