An extraction unit (10) for extracting cartridges (1a;1b) of two different dimensions (da,ha;db,hb) comprises a seat (14,20) for receiving any of these cartridges (1a;1b) for extraction thereof in the seat. The seat is delimited by a first part (20,30,33) and second part (12,13,14) that are relatively movable between a cartridge extraction position and a cartridge loading and/or ejection position over a closure distance (Ca,Cb). The first delimiting part (20,30,33) is extendable and retractable for defining a cartridge cavity having selectively: —a first depth (Ha) for receiving a cartridge (1a) having a first height (ha); and —a second depth (Hb) different to this first depth (Ha) for receiving a cartridge (1b) having a second height (hb) different to this first height (ha). At least one of the delimiting parts (14,20) has a shifter (21,35,38) for compensating the extension and retraction of the first delimiting part (20,30,33) so as to maintain the closure distance (Ca) for the first member position equal to the closure distance (Cb) for the second member position.