This is a Noctua 3 to 2 pin fan adapter cable. It allows you to plug in your 3 pin fan into a 2 pin slot.
Don't buy some junk that was made in someones garage! These are high quality made by Noctua which makes high quality fans and parts.
Item is brand new but without any original packaging. I use the fans for another application and I don't need these adapters that come with.
Ask me about special bulk pricing I will give a killer deal if you need a bunch of these.