To understand that, it helps to know that they will both complement eachother, and improve the overall precision of the calibre.
The Duplex swan-neck fine adjustment is connected to the balance by means of the stud-holder and enables regulation of the anchor symmetry. Adjusting the adjustment screw allows one to turn the entire balance so that the impulse pin is centred in the anchor fork, which optimises the insertion of the pallets
The pallet jewels interact with the escape wheel. As the escape wheel rotates, its teeth engage with the pallet jewels, releasing a small amount of energy to the balance wheel at regular intervals. The pallet jewels are often made of synthetic sapphire or ruby, which are hard and durable materials that reduce friction and wear on the escapement mechanism
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The escape wheel is part of the escapement mechanism. As the mainspring unwinds, it turns the going train gears and rotates the escape wheel. As the escape wheel rotates, it pushes the pallet, which releases a small amount of energy to the balance wheel at regular intervals. This causes the balance wheel to oscillate back and forth, which in turn drives the timekeeping functions of the watch.
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Thus on the right side one can regulate the rate (V/N) and on the left the anchor symmetry – for extreme precision.