@xuwei If you are talking about the Multiple Grippers wiring, the following information can be found in section 3.7 of the manual.Multiple Grippers wiring
It is possible to connect and control up to four grippers on the same UR robot. Only one USB to RS485 converter (ACC- ADT-USB-RS485) must be used. Use M12 splitters (ACC-SPLIT-M12-2:1) to connect all the grippers pigtails to one 10m cable (CBL-COM-2065-10-HF) that connects to the USB to RS485 converter.
Figure 3.7.2: Multiple grippers wiring on Universal Robots.
The section 3.8.1 cover the URCap installation and ID identification of the gripper
Finally the part number for the dual Gripper coupling is AGC-APL-159-002. If you need the STEP file of this coupling, it is available here.