Escapement in 2015 as the most accurate open-air mechanical clock, deviating of a second during 100 days. It continues to run and oscillate ±0.5 seconds around 0.00 seconds of error after 2 years after a barometric correction was applied. A gravity escapement uses a small weight or a weak spring to give an impulse directly to the pendulum. The earliest form consisted of two arms which were pivoted very close to the suspension spring of the pendulum with one arm on each side of the pendulum. Each arm carried a small dead beat pallet with an angled plane leading to it.
Escapement was recognized as a disturbing influence on the isochronism of the balance. Purchasers no longer buy mechanical watches primarily for their accuracy, so manufacturers had little interest in investing in the tooling required, although finally Omega adopted it in 1990. Although a highly ingenious escapement design, the Daniels coaxial nevertheless still needs lubrication to the lever pallet pivots. In addition, because of its geometry the impulse wheel can only have a limited number of teeth, thus it is necessary to have an extra wheel and pinion in the wheel train the pivots of which also need lubricating. Therefore, the advantages