Neoprene rubber provides excellent cushioning. Round end type (thumb part is broken and the outside is rounded. The heel part has nibs, making it easy to put on and take off. Comes with an instep belt to secure your feet. About the Size Chart: Only the L and LL sizes are listed on the product and the size on the outer box and product tag may vary. The actual size of the outer box and product tag are the correct size. Even if the size and different sizes you ordered are listed in the product, we will send you the correct product without any problems.