Modular Power 12pin To 2 Port Pci-e 6+2pin Power Supply Cable Dual Gpu 8pin For Corsair Ax Series Ax650 Ax750 Ax850 - Pc Hardware Cables & Adapters - AliExpress
Amazon.com: EZDIY-FAB RTX 3000 Series 12 Pin to Dual 8 Pin PCIe Sleeved Extension Cable 300 MM- Connector for NVIDIA Ampere GEFORCE RTX 3060ti 3070 3080 FE Funder Edition- Black : Electronics
Antec HCP Platinum Dual 8 Pin to Nvidia RTX30 12 Pin PCIE Modular Cable - MODDIY
Pinout for 12-pin adapter included with RTX 3080 : r/nvidia