Tubular connection element having - a first opening (6, 6'), - a second opening (16, 16'), - a first connection section (8, 8'), - a second connection section (12, 12'), - a nozzle section (14, 14') and - a control region (10, 10'), - wherein the first connection section (8, 8') is connectable to a first connector (30a, 30b, 30c), - wherein the second connection section (12, 12') is connectable to a second connector (30a', 30b', 30c'), - wherein the nozzle section (14, 14') is introducible into the second connector (30a', 30b', 30c'), - wherein the control region (10, 10') is visible from the outside after connecting with the first connector (30a, 30b, 30c) and the second connector (30a', 30b', 30c'), - wherein the first connection section (8, 8') is compressible with the first connector (30a, 30b, 30c) and the second connection section (12,12') is compressible with the second connector (30a', 30b', 30c'), - wherein the connection sections (8, 8', 12,12') are introducible into the corresponding connector (30a, 30b, 30c, 30a', 30b', 30c') and are formed as a support section, - wherein a flange region (11,11') is provided on the external circumferential surface between the first connection section (8, 8') and the second connection section (12, 12') which provides a stop (20, 22) for the connectors (30a, 30b, 30c, 30a', 30b', 30c') and makes the control region (10, 10') available, characterised in that - the second connection section (12, 12') adjoins the first connection section (8, 8') viewed in the flow direction of the medium and the nozzle section (14, 14') adjoins the second connection section (12, 12') and in that the nozzle section (14, 14') is fully introducible into the second connector (30a', 30b', 30c'). - a first opening (6, 6'), - a second opening (16, 16'), - a first connection section (8, 8'), - a second connection section (12, 12'), - a nozzle section (14, 14') and - a control region (10, 10'), - wherein the first connection section (8, 8') is connectable to a first connector (30a, 30b, 30c), - wherein the second connection section (12, 12') is connectable to a second connector (30a', 30b', 30c'), - wherein the nozzle section (14, 14') is introducible into the second connector (30a', 30b', 30c'), - wherein the control region (10, 10') is visible from the outside after connecting with the first connector (30a, 30b, 30c) and the second connector (30a', 30b', 30c'), - wherein the first connection section (8, 8') is compressible with the first connector (30a, 30b, 30c) and the second connection section (12,12') is compressible with the second connector (30a', 30b', 30c'), - wherein the connection sections (8, 8', 12,12') are introducible into the corresponding connector (30a, 30b, 30c, 30a', 30b', 30c') and are formed as a support section, - wherein a flange region (11,11') is provided on the external circumferential surface between the first connection section (8, 8') and the second connection section (12, 12') which provides a stop (20, 22) for the connectors (30a, 30b, 30c, 30a', 30b', 30c') and makes the control region (10, 10') available, - the second connection section (12, 12') adjoins the first connection section (8, 8') viewed in the flow direction of the medium and the nozzle section (14, 14') adjoins the second connection section (12, 12') and in that the nozzle section (14, 14') is fully introducible into the second connector (30a', 30b', 30c').