Teachables Trundle Wheel - Plastic, Set of 10Measuring long distances is made efficient and engaging with this set of 10 plastic trundle wheels, designed for ease of use in classroom, outdoor, or field based learning. Each trundle wheel is equipped with a loud clicking device that can be set to three positions: off, every 10 cm, or every metre, allowing flexibility for different measuring activities. The wheel can be used in either direction or produces an audible click with every full rotation,