The strap, which bonds a calfskin-inlay leather outer layer with an inner layer of rubber, is also reminiscent of 1930s motor racing tradition, in which sturdy leather straps were commonly found on drivers’ overalls and in the cockpits and bonnets of their vehicles. Stainless steel bracelets with fine-adjustment clasps are also available. The solid, stainless-steel caseback features an engraved illustration of the Mercedes W25 Silver Arrow race car.
IWC’s in-house chronograph movement, Caliber 89361, powers the watch’s signature function, a chronograph with a flyback mechanism. The dial’s design enables stopped hours and minutes to be read easily on the same subdial at 12 o’clock. The central seconds counter can be used in conjunction with the tachymeter scale around the dial to calculate speeds. The flyback function is engineered with racing pit stops in mind: pressing the reset button returns the seconds hand instantly to zero and immediately starts timing another sequence. IWC’s Pellaton winding system — developed by technical director and longtime Mercedes racing enthusiast Albert Pellaton — enables the movement to maintain a power reserve of 68 hours.
For wallpaper images of the Silberpfeil and other IWC Ingenieur watches, click here.
This article was originally published on April 19, 2013, and has been updated.