Brand: Helbros

Model: Commander (from their Invicible line)

Era: Late 1960s / Early 1970s

Movement: Valjoux 7733 manual wind chronograph. Keeping good time. Chronograph functions work - Top pusher is start/stop, Bottom pusher is reset. Service history unknown. 

Dial: Small marks above and below Helbros text and between 1-2 o'clock markers (see photos)

Strap: 18mm Fluco German-made black leather

Lug width: 18 mm
Case width excluding crown: 37.3 mm
Lug to lug: 44.6 mm
Thickness: 12.65 mm

Buyer pays $25 insured S&H in U.S.