Order by 4pm Monday to Friday for Next Day Delivery Fulfilled by WatchShop - Reach optimum air speed with the SlipStream Aero SL157511. A 42mm black plated chronograph watch with rotating inner slide rule and chronograph functionality. The sunburst finished black dial is enhanced with crisp white markings and information for precise timing calculations. The cut-away black leather strap and SlipStream buckle ensure supreme comfort.