The Dacia modular roof rails / bars (the type that adapt from fitting lengthways to across the roof) sit very close to the roof, and are wider and deeper than most cross bars, so many roof mounted accessories are not compatible.
We recommend a a Kamei roof box that comes with U-bolts which will work with these bars. These include boxes from their Husky and Delphin range. Please note, the Kamei Fosco and Oyster roof box ranges do not fit Dacia Modular bars.