The design solution is based on a simple but very strong visual and functional concept: the cross. The chair's legs, support for the backrest, support for the armrest and writing tablet, ganging connectors, stacking bumpers, and beam supporting the seat all come together at the cross. It is also the key point onto which new elements can be added after the chair has been bought, such as armrests and writing tablets. The user is able to install these accessories with a simple hexagonal wrench. The backrest of this chair can flex backwards, supporting the user in both the relaxed position when listening to a lecture or an erect one when writing notes. The cross is the symbol of the chair's multifunction mission; reduced to a minimum, it is a design tour de force. The structure is made of aluminum, c shaped in section, die-cast. The flexing backrest is made in ABS plastic. The tilt-up seat is produced also in ABS.
Stacker is to be used by the general public for periods of time ranging from 15 minutes to 2-3 hours, in schools, waiting areas, auditoria, offices, and factories. This typology of chair must stack vertically for storage and gang safely in rows. Moreover, to sharpen its competitive edge, the seat of this type of chair must be able to tilt up vertically. This allows increasing the number of rows by reducing the distance between rows, while facilitating the passage of people entering or leaving the rows. Furthermore, this type of chair also needs to be equipped with a writing tablet, for either left or right-handed users. This writing tablet must tilt up to allow the user to get up or sit down, while at the same time, it must also be able to collapse automatically out of the way in case of a panic.