Small ("S") JamChuck kit includes the base and 3 semi-sphere extensions. Made in the USA! Our Innovative and versatile jam chuck securely holds your workpiece, allowing you to finish your turning with ease. You can choose from multiple mountable semi-sphere extensions to ensure a tight fit into your workpiece cavity. Be sure to add it to your tool kit - no need to waste time making your own wooden jam chuck versions for different cavities The "S" kit will fit into a workpiece with an opening ranging from 0.375" to 2.25" (1cm to 5.7cm) diameter. The "S" JamChuck base unit is held in the lathe's chuck. Extensions are mounted onto the base unit and then onto each other as needed to fit inside the workpiece cavity. Color of products might be different from what is shown.