This is a stainless steel Eberhard Aviograf 31018. It has a leather strap with a stainless steel tang buckle, and an acrylic crystal. It includes a screw down winding crown, rectangular chronograph push buttons, and a solid snap down case back engraved with "AVIOGRAF-EVERHARD & CO.-LA CHAUX-DE-FONDS-FODE 1887-REF. 31018." The 40mm diameter solid three-body case, gently curved lugs, and stepped bezel, are polished/brushed. The dial is "reverse panda" black with aged luminous gold-rimmed Arabic numeral hour markers, luminous white baton hands, and a luminous center sweep seconds hand with an arrow tip. There is an inner luminous white minute/one-fifth second scale, an outer 100-second track, and around the perimeter is a white luminous tachymeter scale to 1000 UPH. It has three recessed silver guilloche subsidiary dials with black markers, Arabic numerals, and black hands, including a running small seconds register at 9 o'clock, a 12-hour chronograph totalizer at 6 o'clock, and there is a 30-minute totalizer at three o'clock. It has a 40-hour power reserve at full wind, and it's run with the same Lemania 1873 caliber that was in the Omega Speedmaster (Omega 861) that went into space. The 12.5mm thick case, dial, and movement are all signed. This Eberhard Aviograf 31018 has a mechanical manual winding, Lemania 1873 caliber (same as the Omega Speedmaster) movement. It's rhodium plated with fausses cotes embellishment, and it's constructed with 18 jewels, a straight-line lever escapement, and a shock absorber device. It includes a monometallic balance, a self-compensating flat balance spring, and an index regulator. The mechanism oscillates at a frequency of 21,600 vph (3 Hz). This Eberhard Aviograf Chronograph 31018 was introduced in 1990, and was produced until 1999.
A beautiful watch with a great movement!