Collar, specifically for connecting channeling modules for air processing systems, said channeling modules being of a type comprising a tubular body extending along a predetermined path between a first and second longitudinal ends, said tubular body having, at said longitudinal ends, respective shoulders radially emerging from the body according to a direction emerging from the latter, said collar comprising: at least one main body made of sheet, particularly and in a non limiting way made of metal material, extending along a predetermined path suitable for substantially defining a crown, said main body having, according to a cross-section, a shape having at least one concave portion defining a housing seat and at least one abutment portion emerging from a free edge of the housing seat according to a direction emerging from the latter, the main body being configured for being placed around aligned channeling modules and having the respective shoulders facing and contacting each other, the concave portion of the main body being configured for embracing at least partially the contacting shoulders of the aligned modules, while the abutment portion being configured for substantially abutting an outer side surface of the tubular body of a channeling module, the main body having at least one first and at least one second end portions (2a, 2b) which, in an operative condition of the collar, are configured for operating in proximity to each other, the main body having an opening at least at said first and second end portions (2a, 2b), at least one first tab integrally part of the main body, at the first end portion, and transversally emerging away from said body, at least one second tab integrally part of the main body, at the second end portion, and transversally emerging away from said body, the second tab substantially facing said first tab, the concave portion extending at least to a lying plane of at least one of said tabs, characterized in that the first and second tabs (6, 7) are a prolongation of the abutment portion of the main body, the first and second tabs (6, 7) extending as a prolongation of the main body exclusively from the abutment portion, wherein the first and second tabs (6, 7) do not emerge from the concave portion. at least one main body made of sheet, particularly and in a non limiting way made of metal material, extending along a predetermined path suitable for substantially defining a crown, said main body having, according to a cross-section, a shape having at least one concave portion defining a housing seat and at least one abutment portion emerging from a free edge of the housing seat according to a direction emerging from the latter, the main body being configured for being placed around aligned channeling modules and having the respective shoulders facing and contacting each other, the concave portion of the main body being configured for embracing at least partially the contacting shoulders of the aligned modules, while the abutment portion being configured for substantially abutting an outer side surface of the tubular body of a channeling module, the main body having at least one first and at least one second end portions (2a, 2b) which, in an operative condition of the collar, are configured for operating in proximity to each other, the main body having an opening at least at said first and second end portions (2a, 2b), at least one first tab integrally part of the main body, at the first end portion, and transversally emerging away from said body, at least one second tab integrally part of the main body, at the second end portion, and transversally emerging away from said body, the second tab substantially facing said first tab, the concave portion extending at least to a lying plane of at least one of said tabs,