Enhance your K'NEX car building experience with these four brand new large hollow wheels. Each tire comes with a silver pulley for added functionality. These wheels are compatible with K'NEX products and are a perfect replacement part for any broken or worn-out wheels. The silver color adds a sleek touch to your designs and their size of 3.5 inches makes them ideal for creating larger structures. These wheels are recommended for ages 5 and up and come in a polybag packaging for added convenience.