A&S 1615 ist ein calibre by Arnold & Son.
One barrel transfers energy to the second one when needed. Essentially, as the first barrel winds the second one, the power reserve indicator of the first barrel goes down, while the second one goes up – making for an accurate and intriguing readout. The two mainspring barrels supply the hand-wound calibre with an amazing 90 hours of power reserve, and provide a more constant force to the wheel train.
The gear train runs vertically in a linear format connecting the two barrels at six o’clock to the balance wheel at twelve o’clock, and endowing the movement with its pyramid structure. The bridges are designed so that all of the wheels, the two mainspring barrels, the escapement and balance wheel are all magnificently visible from the dial side.
The calibre is used with the Arnold & Son Time Pyramid Guilloché.