Series 31

Series 31

The pocket watch movement that has been redesigned to feature an indirect central second hand makes this watch an elegant choice. A key feature of the movement remains the secret of the wearer – the second stop.

To precisely set the time of a wrist watch most movements are equipped with a second stop – when the crown is wound, the second hand doesn’t move. The seconds zeroing is a much rarer design.

When the crown is wound, the second hand continues to run until it reaches “60” and then it automatically stops – thus it is possible to use a time signal to set the watch to the second.

Model Overview Series 31

31.HS-12.1

Modell 31.HS-12.1

Bezel
fixed bezel

Case
stainless steel polished, case sides in satin finish

Dial and Hands
deep black dial, hands made in steel

Special features
Nivarox hairspring, swan neck micrometer

31.HS-12.2

Modell 31.HS-12.2

Bezel
fixed bezel

Case
stainless steel polished, case sides in satin finish

Dial and Hands
deep black dial, hands made in steel

Special features
Nivarox hairspring

31.HS-14.2

Modell 31.HS-14.2

Bezel
fixed sandblasted bezel

Case
stainless steel bead-blasted

Dial and Hands
deep black dial, hands made in steel

Special features
Nivarox hairspring

Technical details

Movement

  • Calibre HS 81
  • Base: UNITAS 6497 Lépine. Modified as per a construction by Helmut Sinn
  • indirect center second
  • second stop at 60 when crown is pulled
  • 18 jewels
  • 18000 vibrations per hour; 2.5 Hz.
  • Movement diameter 16 1/2''' (36,6 mm)
  • Incabloc shock protection
  • Glucydur balance
  • Nivarox hairspring
  • Movement decorated with Geneva Stripes , blued screw hads, crown wheel and ratchet wheel with solar finish
  • Power reserve approx. 40 hours

Functions

  • Hours, minutes, indirect center second
  • Second stop at 60 when crown is pulled

Case

  • Case made of stainless steel, polished
  • sapphire crystal glass, anti-reflective on the interior
  • screwed back with crystal glass
  • Pressure resistant up to 10 bar

Dimensions and Weight

  • Case diameter: 41.9 mm
  • Case thickness: 13.7 mm
  • Band lug width: 22 mm
  • Weight without strap: 71 Gramm

Straps 22 mm

Leather Strap Arizona

Leather Strap Arizona Black

Black Cowhide with alligator embossing.
Available with a pin or folding clasp.

Cases 22 mm Type 42 Type 31
ideal wrist circumference in mm 192,3 mm 191 mm
ideal wrist circumference in inch 7.6 in 7.5 in
max. wrist circumference in mm 212,3 mm 211 mm
max. wrist circumference in inch 8.4 in 8.3 in
min. wrist circumference in mm 172,3 mm 171 mm
min. wrist circumference in inch 6.8 in 6.7 in

Wrist circumference specifications are approx. values and depend on the individual wearing habits.

Leather Strap Monza

Dull finished calf leather with contrast stitching, BR-padded
Available with a pin or folding clasp.

Cases 22 mm Type 42 Type 31
ideal wrist circumference in mm 187,3 mm 186 mm
ideal wrist circumference in inch 7.4 in 7.3 in
max. wrist circumference in mm 207,3 mm 206 mm
max. wrist circumference in inch 8.2 in 8.1 in
min. wrist circumference in mm 169,3 mm 168 mm
min. wrist circumference in inch 6.7 in 6.6 in

Wrist circumference specifications are approx. values and depend on the individual wearing habits.

Leather Strap Starfighter Pilot

Leather Strap Starfighter Pilot

Black leather strap made of intensely grained cow hide with a subtle contrast stitching.
Available with a pin or folding clasp.

Cases 22 mm Type 42 Type 31
ideal wrist circumference in mm 195,3 mm 194 mm
ideal wrist circumference in inch 7.7 in 7.6 in
max. wrist circumference in mm 213,3 mm 212 mm
max. wrist circumference in inch 8.4 in 8.3 in
min. wrist circumference in mm 176,3 mm 175 mm
min. wrist circumference in inch 6.9 in 6.9 in

Wrist circumference specifications are approx. values and depend on the individual wearing habits.

Leather Strap Vintage Black

High-quality leather strap with red stitching, at the tip of the strap and at lug ends
Leather uppers, matte; Underside leather both cowhide. The thickness of the strap is approx. 3,3 mm.
Available with a pin or folding clasp.

Cases 22 mm Type 42 Type 31
ideal wrist circumference in mm 200,3 mm 199 mm
ideal wrist circumference in inch 7.9 in 7.8 in
max. wrist circumference in mm 215,3 mm 214 mm
max. wrist circumference in inch 8.5 in 8.4 in
min. wrist circumference in mm 181,3 mm 180 mm
min. wrist circumference in inch 7.1 in 7.1 in

Wrist circumference specifications are approx. values and depend on the individual wearing habits.

Leather Strap Antique

Leather Strap Antikleder

Pull up leather with laquered edging and colored stitch.
Available with a pin or folding clasp.

Cases 22 mm Type 42 Type 31
ideal wrist circumference in mm 193,3 mm 192 mm
ideal wrist circumference in inch 7.6 in 7.6 in
max. wrist circumference in mm 213,3 mm 212 mm
max. wrist circumference in inch 8.4 in 8.3 in
min. wrist circumference in mm 171,3 mm 170 mm
min. wrist circumference in inch 6.7 in 6.7 in

Wrist circumference specifications are approx. values and depend on the individual wearing habits.

Rubber Strap Glatt

Rubber Strap Glatt

Black rubber strap, smooth surface, incl. a laser engraved folding-clasp satinated or bead-blasted.
Available with a pin or folding clasp.