Wear it over a flight jacket or a winter coat and it still fits. The Marathon SSNAV Auto Sterile, reference WW194029SS-0802-KIT, comes on an extra-long ballistic nylon strap, giving this black-dial Steel Navigator Automatic the length to go over sleeves or around larger wrists.

Pilots have long strapped their watches over the cuff of a flight suit for quick reference, and the extra-long one-piece ballistic nylon makes that easy. Made to the MIL-S-46383B military standard, it threads beneath the case so the watch stays put even if a spring bar fails, and the generous length still leaves enough tail to tuck in neatly when worn on a bare wrist.

The watch is a self-winding take on Marathon's pilot's classic. A Swiss Sellita SW200-1 automatic movement with 26 jewels and about 41 hours of reserve runs inside a 41mm 316L stainless steel case that is just 11.5mm thick. The sterile black Type II dial carries no insignia, letting bold tritium-lit markers and hands do the work. A screw-down crown and sapphire crystal give it 10 ATM of water resistance and plenty of scratch protection. The bi-directional 12-hour bezel, first designed for U.S. Air Force crews with Kelly Air Force Base in 1986, keeps a second time zone in view whenever you need it.

SSNAV Auto WW194029SS-0802-KIT: Key Specs

• Reference: WW194029SS-0802-KIT
• Case: 41mm 316L steel, 11.5mm, 48mm lug to lug
• Movement: Sellita SW200-1 Swiss automatic, 26 jewels
• Power reserve: about 41 hours
• Water resistance: 10 ATM via screw-down crown
• Crystal: sapphire
• Bezel: bi-directional, 12-hour scale
• Dial: sterile black Type II with tritium lume
• Strap: extra-long black ballistic nylon, 20mm

Extra strap, sterile dial and a mechanical heartbeat underneath.