A circular plug connector comprising: an outer coupling ring having a cavity extending between a front and a rear , the outer coupling ring including a retaining element proximate to the rear , the outer coupling ring including a mating element proximate to the front configured to be coupled to a mating connector ; a plug shell extending between a front and a rear , the plug shell housing one or more plug contacts configured to be coupled to the mating connector , the plug shell having a front body at the front configured to be coupled to the mating connector , the plug shell having a rear body at the rear , the plug shell including a mid-body between the front body and the rear body having a rear facing support surface ; characterized in that the circular plug connector further comprises a self-supporting compression element surrounding the rear body , the self-supporting compression element extending between a front and a rear , the self-supporting compression element including a spring element at the front , the self-supporting compression element including a retaining shim support at the rear , the retaining shim support being integral with the spring element as a unitary monolithic body, the retaining shim support being received in the retaining element to fix the self-supporting compression element relative to the outer coupling ring , the spring element engaging the rear facing support surface to support the plug shell within the cavity of the outer coupling ring , the spring element being compressible relative to the retaining shim support to allow the plug shell to move axially within the cavity of the outer coupling ring . an outer coupling ring having a cavity extending between a front and a rear , the outer coupling ring including a retaining element proximate to the rear , the outer coupling ring including a mating element proximate to the front configured to be coupled to a mating connector ; a plug shell extending between a front and a rear , the plug shell housing one or more plug contacts configured to be coupled to the mating connector , the plug shell having a front body at the front configured to be coupled to the mating connector , the plug shell having a rear body at the rear , the plug shell including a mid-body between the front body and the rear body having a rear facing support surface ; characterized in that the circular plug connector further comprises a self-supporting compression element surrounding the rear body , the self-supporting compression element extending between a front and a rear , the self-supporting compression element including a spring element at the front , the self-supporting compression element including a retaining shim support at the rear , the retaining shim support being integral with the spring element as a unitary monolithic body, the retaining shim support being received in the retaining element to fix the self-supporting compression element relative to the outer coupling ring , the spring element engaging the rear facing support surface to support the plug shell within the cavity of the outer coupling ring , the spring element being compressible relative to the retaining shim support to allow the plug shell to move axially within the cavity of the outer coupling ring . <EOS>