A reservoir (1) for rod-like elements (R) for tobacco industry, configured to be connected to a first feeding duct (2), to a second feeding duct (3) and to a receiving duct (10) for receiving the rod-like elements (R) from the reservoir (1), wherein the reservoir (1) has adjustable capacity and is coupled with filling level sensing means (14, 15) for sensing a filling level of the reservoir (1). The reservoir comprises two chambers (12, 13) having adjustable capacity and separated by a partition (24). The first chamber (12) is coupled with a first filling level sensing means (14) for sensing a filling level of the first chamber (12), and the second chamber (13) is equipped with a second filling level sensing means (15) for sensing a filling level of the second chamber (13).