PCI Express Extension Cable: 16x to 16x with Powered Risers / Molex Fits MOBO slot: 16x to 16x Powered Risers, works with all PCI BUS slots. Length: 19cm This is a powered cable, however the power is optional as you are not required to use the Molex. It is recommended to connect the Molex to the power supply if you are running 3 or more cards. The molex provides redirection of power, and less changes of damaging your motherboard when used. This cable is used for graphic cards specializing in Cryptocurrency and provide relief from the motherboard. Because they allow the cards to be placed in a custom setup, extension cables allow extensive reduced temperatures of your cards.