Exterior sub-assembly for a timepiece or watch or piece of jewellery

An exterior sub-assembly for a timepiece, or for a watch, or for a piece of jewellery, comprising a first component having rims protruding from a first skirt alternated with first recesses, and a second component including wings protruding from a second skirt alternated with second recesses, arranged to occupy a first disassembled position of insertion in which said first component (1) and said second component have a first angular orientation with respect to each other, or to occupy a second, assembled and locked position in which said first component and said second component have a second angular orientation with respect to each other, different from said first angular orientation, and are held axially in a bayonet fitting between at least two said rims and at least two said wings, characterized in that said sub-assembly comprises at least one third component in the form of a ring, which is inserted between said first component and said second component and comprising a ring-like element housed inside a groove comprised in at least said first component or said second component, and said third component includes at least one rotational stop, with respect to said first component or second component, and at least one radially recessed or respectively radially protruding resilient area, arranged to cooperate, in a plane passing into said groove, in an angular indexing and locking arrangement with a lug or respectively a housing, comprised in whichever of said first component and second component is free to rotate with respect to said third component.