Assembly of a band portion on a watch middle

A device for fastening a band portion to a watch middle, comprising

• a connecting element, intended for a connection to a band portion and to a watch middle, and
• two distinct arbors, each arranged in a respective arbor housing provided within the connecting element or within the watch middle, and capable of occupying a projecting position in which an end portion of each respective one of the arbors is in a projecting position relative to the respective arbor housing, enabling the respective arbor to enter a hole of the watch middle or a hole of the connecting element, respectively, in order to fasten the connecting element and the watch middle using the two arbors,
• wherein at least one of the two arbors is movably mounted within the respective arbor housing so as to be able to also occupy a retracted position within the respective arbor housing to enable the connecting element to be separated from a watch middle,
• wherein the arbor housing incorporates a return element acting elastically on the at least one arbor and urging the at least one arbor to remain in the projecting position,
• the arbor housing comprising a stop element arranged coaxially with the at least one arbor in the arbor housing and adapted to be attached in and removed from the arbor housing, the stop element being attached in the arbor housing coaxially with the at least one arbor, and comprising a stop on which a shoulder of the at least one arbor comes to bear in the projecting position, the stop element comprising a central opening within which the at least one arbor moves when switching between the retracted position to the projecting position, and an actuating feature at an end of the stop element, the actuating feature being oriented toward an outside of the arbor housing to allow the actuating feature to be mounted and removed using a tool, and the at least one arbor comprising a specific shape complementary to a shape of the actuating feature of the stop element so as to enable the at least one arbor and the stop element to be actuated simultaneously using the same tool.