What is the strap width and length? What wrist sizes does it support?

Our silicone strap is 20mm width and 248mm length (buckles included). The leather strap is 20mm width and 258mm length (buckles included). The steel strap is 20mm width and 208mm length. The strap is designed easily to change with any other of your favorite watch straps. Our onyx watch strap will come with 6 extra links.