MALTESE CROSS
Maltese cross is a mechanism which allows to isolate the best cocking turns of a cylinder. This mechanism is located under the barrel drum and is composed of three to four components, the two main ones being a cross cock, slightly off-center, and a finger attached to the barrel shaft.
This mechanism regularly present on the parts of higher quality had all its direction until the middle of the XXth century on the parts equipped with spring of blue cylinder. These springs had a force curve which was very strong at the beginning of cocking and weak at the end of cocking. Thus, having a Maltese cross mechanism that isolated the first and last of the seven cocking turns of a barrel to keep the best five made sense.
This mechanism increases the precision but reduces the power reserve. It might also make sense to use it on modern springs where the force curve always varies a little over the two extreme cocking turns.
Maltese cross or similar systems are almost always present on marine chronometers which are also often equipped with fusees.