foam wheel to fit standard 10mm or 3/8 inch endpin. There's a flat notch on two sides to stop it twisting round whichever way you like to walk with it.
Other endpin sizes: the most common endpin diameter is 10mm or 3/8" but choose which size shaft you need from 8mm, 10mm, 12mm, 14mm, 16mm or 3/8 inch in the drop down menu before clicking the "Buy Now" button.