CITIZEN automatic chronograph so called Bullhead, self winding, reference 4-901177 K, Japan around 1970, metal case including original bracelet with deployant clasp, screwed down stainless steel case back, blue contrast dial, 30 minutes- & 12 hour-register, day & date, 23 jewels, calibre 8110A, diameter approx. 39 mm, length approx. 21 cm, signs of use due to age, overhaul recommended at buyer's expense, condition 3, property of a collector