Jaw
6177
Reverso Duetto classique is a the model
launched after the popular Duetto but in classique size. Except for the size it also has an additional small seconds hand at 6 o'clock on the front.
(Stainless Steel Reverso Duetto Classique with leather strap)
Based on the Calibre 865, it was one of the best selling women model for some years...
The 256.84.20 model you mentioned is the Stainless Steel model with leather strap. A variety of colours strap are available.
(JLC Calibre 865, Mechanical manually wound movement indicating time on both sides with small seconds on the front, 21600vph, 19 jewels, 130 parts,3.45mm high)
Here are some of the specs:
Movement:
Mechanical manually wound movement, crafted, assembled and decorated by hand. 130 parts, 21600vph, power reserve of about 50 hours.
Functions:
Front - Hour, minute, small seconds
Back - Hour, minute, identical to displays on the front.
Case:
Reversible, over 50 parts, classic size, sapphire crystal hardness No. 9
Gem-Setting:
32 diamonds, approx 0.31 carats, crown set with an inverted diamond of about 0.08carat for gold models. Full cut F-G Top Wesselton VVS1 diamonds.
Straps/Bracelet:
Leather - alligator strap and folding clasp
Metal - patented double-blade clasp
Material available
18-carat white gold
18-carat yellow gold
stainless steel.