Fitting comprising a fitting body having a fluid passage , a first pipe socket for the connection of a first pipe portion and a second pipe socket for the connection of a second pipe portion with an external thread , and also comprising a coupling unit , which is arranged on the second pipe socket and is intended for releasably connecting the second pipe portion to the second pipe socket , wherein the coupling unit comprises a union nut , which is pivotably mounted on the fitting body and has a cylindrical interior space , which is delimited by an inner surface , wherein the interior space encloses the second pipe socket such that an accommodating space is created between the interior space and pipe socket , it being possible for the second pipe portion which is to be connected to be accommodated in the accommodating space, wherein the inner surface has arranged on it an internal thread , which can be brought into engagement with the external thread of the second pipe portion , and wherein arranged on the outside of the second pipe socket is a sealing element , which interacts with the inner side of the second pipe portion , wherein the coupling unit comprises a securing element , which can provide rotary locking between the second pipe portion and the union nut to counter a release movement of the union nut , characterized in that the coupling unit further comprises a torque-limiting element , which limits the torque applied to the union nut during assembly, in that a drive ring is arranged on the outside of the union nut , wherein the torque-limiting element is arranged between the drive ring and the union nut , and wherein a rotary movement of the drive ring can be transmitted to the union nut via the torque-limiting element , and in that the drive ring has a cavity , in which the union nut is placed, wherein the cavity is designed such that the union nut is located essentially entirely in the cavity . comprising a fitting body having a fluid passage , a first pipe socket for the connection of a first pipe portion and a second pipe socket for the connection of a second pipe portion with an external thread , and also comprising a coupling unit , which is arranged on the second pipe socket and is intended for releasably connecting the second pipe portion to the second pipe socket , wherein the coupling unit comprises a union nut , which is pivotably mounted on the fitting body and has a cylindrical interior space , which is delimited by an inner surface , wherein the interior space encloses the second pipe socket such that an accommodating space is created between the interior space and pipe socket , it being possible for the second pipe portion which is to be connected to be accommodated in the accommodating space, wherein the inner surface has arranged on it an internal thread , which can be brought into engagement with the external thread of the second pipe portion , and wherein arranged on the outside of the second pipe socket is a sealing element , which interacts with the inner side of the second pipe portion , wherein the coupling unit comprises a securing element , which can provide rotary locking between the second pipe portion and the union nut to counter a release movement of the union nut , characterized in that the coupling unit further comprises a torque-limiting element , which limits the torque applied to the union nut during assembly, in that a drive ring is arranged on the outside of the union nut , wherein the torque-limiting element is arranged between the drive ring and the union nut , and wherein a rotary movement of the drive ring can be transmitted to the union nut via the torque-limiting element , and in that the drive ring has a cavity , in which the union nut is placed, wherein the cavity is designed such that the union nut is located essentially entirely in the cavity . <EOS>