When I put the Deepstar 39mm on a NATO it felt as though the strap made the case feel much thicker and more top-heavy on my wrist. Switching back to the included Tropic rubber, the difference is remarkable and it highlights just how much a specific strap can help to manage link the way a watch interacts with your wrist and manages its own bulk. The rubber wears flat and comfy on link my wrist while also perfectly suiting the overall link style of the Deepstar.