The IQ D-rig is a fabulous rig to use for wary carp, thanks to its inherent stiffness and the superb anti-eject properties that the swivel sliding on the large D arrangement gives.
The rigs are available in barbed and barbless variants, and in sizes four, which is tied to 15lb IQ2, six, which is tied to 12lb IQ2 and eight, which is tied to 10lb IQ2.