Normal wristwatch has a simple work to show the time. In that kind of wrist watch only needed things are a hand of hour and for the minutes and power reservoir to keep track of running time. Thunderbolt HM4 has a hand of hour, minutes, and a power reserve indicator. 

The case of thunderbolt HM4 made from titanium which imparts lightweight and strength with a sapphire centre section offering a view into the engine. The limited editions HM4 Razzle Dazzle and Double Trouble take the aviation theme even further with real rivets in their fuselages and hand painted nose art inspired by the rebellious paintings on WWII aircraft, while HM4 RT offers an altogether more luxurious way to fly. Thunderbolt’s engine is the result of three years effort of development.. Each of the 300-plus components – including the regulator and even the screws – was developed specifically for this anarchistic caliber. 

  • HM4 Thunderbolt: Grade 5 Titanium and sapphire
  • HM4 Razzle Dazzle and Double Trouble: Grade 5 Titanium and sapphire, hand painted nose art, limited editions of 8 pieces each
  • HM4 Thunderbolt RT: 5N red gold, Grade 5 titanium and sapphire. Limited edition of 18 pieces
  • HM4 Final Edition: Blackened titanium and sapphire. Limited edition of 8 pieces closing the HM4 series in 2013
  • Dimensions: 54mm wide x 52mm long x 24mm high
  • Number of components: 65 (67 for HM4 Final Edition)

Engine
  • Three-dimensional horological engine developed 100% by MB&F
  • Manual winding with two mainspring barrels in parallel
  • Power reserve: 72 hours
  • Balance frequency: 21,600bph/3Hz
  • Number of components: 311
  • Number of jewels: 50

Functions
  • Hours, minutes and power reserve indicator
  • Hours and minutes on right dial, power reserve indicator on left dial
  • Separate crowns for time setting and winding

Strap & Buckle
  • Hand-stitched calfskin strap with titanium/white gold or red gold custom designed folding buckle attached to articulated lugs.
  • Razzle Dazzle and Double Trouble: Authentic vintage leather strap crafted from Swiss military bags with contrasting white hand stitching. Titanium/white gold custom designed deployment buckle.