Apparatus for handling bottles, comprising: - a first and a second conveyor belt to advance said bottles, said first conveyor belt having a first (A') direction of advancement and said second conveyor belt having a second (A") direction of advancement, wherein said first (A') and second (A") directions of advancement are incident to each other; - a deflector device to connect said first and second conveyor belts, comprising an outer guide body to contain said bottles during their advancement, and an inner guide body to contain said bottles on the opposite side with respect to said outer guide body, said inner guide body comprising a belt to advance said bottles, closed in a loop on respective pulleys (322, 323, 324) of which at least one is motorised, said apparatus comprising conditioning means to change the configuration of said inner guide body by varying its relative position with respect to said outer guide body and the radius of curvature of said advancing belt, characterised in that said conditioning means comprise an element for pushing a respective element for tensioning said belt, said pushing element comprising adjustment means configured to vary the thrust applied on said tensioning element and said curvature of said belt; and in that said tensioning element being positioned within said ring defined by said belt, said tensioning element being elastically deformable to cause said belt to adopt multiple different radii of curvature; wherein said inner guide body comprises a cover, wherein said tensioning element comprises a plurality of guide pins designed to engage in a sliding fashion within respective slots formed in said cover to guide said tensioning element in its elastic deformation. - a first and a second conveyor belt to advance said bottles, said first conveyor belt having a first (A') direction of advancement and said second conveyor belt having a second (A") direction of advancement, wherein said first (A') and second (A") directions of advancement are incident to each other; - a deflector device to connect said first and second conveyor belts, comprising an outer guide body to contain said bottles during their advancement, and an inner guide body to contain said bottles on the opposite side with respect to said outer guide body, said inner guide body comprising a belt to advance said bottles, closed in a loop on respective pulleys (322, 323, 324) of which at least one is motorised, said apparatus comprising conditioning means to change the configuration of said inner guide body by varying its relative position with respect to said outer guide body and the radius of curvature of said advancing belt, characterised in that said conditioning means comprise an element for pushing a respective element for tensioning said belt, said pushing element comprising adjustment means configured to vary the thrust applied on said tensioning element and said curvature of said belt; and in that said tensioning element being positioned within said ring defined by said belt, said tensioning element being elastically deformable to cause said belt to adopt multiple different radii of curvature; wherein said inner guide body comprises a cover, wherein said tensioning element comprises a plurality of guide pins designed to engage in a sliding fashion within respective slots formed in said cover to guide said tensioning element in its elastic deformation.