MONT Stubline d.o.o. is a factory based in Serbia which specializes in design/manufacture/installation of components to biogas plants. We started in this industry in 2011. by supplying Bigadan and Xergi (now Nature Energy) with various tanks (slurry pre-mix, hygienization, heat storage) and, most notably, double-helix (HEX) heating system for biomass/biomass and biomass/water applications. Over the years, we became specialists for double-helix system for various biomasses.