The mechanism allows to transform a sofa into a sleeping bed. The unfolding consists in pulling the seat, then the backrest goes down automatically and we receive two plate surface to lie down. The folding relies on unblocking the special handle located behind the backrest and pulling it up together with the whole construction. The solution consists of metal frame and mechanism, wooden slats, and plastic holds. The main adventage of that solution is really high sleeping comfort thanks to applying two separate materasses of up to 14 cm thickness.