Firstly- let me say this... if you have purchased a very expensive graphics card why can manufacturer not provide these adapters in the box?? it's like buying a car with wheels and you have to go and buy the tyres!!! - really annoying!!
Ok- minor rant out of the way, I purchased these to power a recently purchased Nvidia 2080 graphics card. All new graphics cards these days require additional power and this product fits the bill- quick and easy to install, they plug into the molex connectors on a standard pc powersupply and power the card. Quality seemed ok, with the pins in the connector solidly fixed. good price for the adapter, but as mentioned, a really bug bear that you have to buy these when really they should come supplied with your new card.