Escapement-making consists of making numerous angle adjustments to the pallets. This is particularly true for the penetration of the rubies of the pallets in the escapement wheel. A standard quality watch has a penetration representing approximately 1/3 of its impulse plane whereas a high quality watch has a lower penetration which corresponds to approximately 1/4 of the impulse plane. Adjustments will also be made to the fork and guard-pin towards the balance axis and also to the height divisions. Escapement-making is an important part of the watchmaker’s apprenticeship, which can take about two to three months out of a total training period of three to four years.