A push-button equipment includes a pressel; a mounting collar for being installed on a base, such as a button panel, the mounting collar including a seat for receiving the pressel; the pressel including a pressing face for receiving a press of a user and being insertable in the seat of the mounting collar in a forward direction orthogonal to the pressing face. The pressel is movable in the seat into a locked position by rotating it in the seat around a rotational axis extending in said direction orthogonal to the pressing face. In said locked position the collar blocks the pressel from moving in backwards direction orthogonal to the pressing face out from the seat. A pressel for the push-button equipment and a push-button arrangement of an elevator are also disclosed.