Our pre-wired LEDs are nothing but quality. The 9v 3mm uv purple led puts out a nice color that is sure the illuminate your product or project. Our 3mm pre-wired leds have built in resistors so that they will work with the voltage that they are rated for. There is no need for you to add any additional resistors. The only thing you need to do is add power ground and they will illuminate. It doesnt get much easier than that.The 3mm pre-wired leds come with a built in resistor, all connections are heat shrinked in order to protect them and there is sufficient wire lead on all of them.This single setup works well with the following voltages (you dont have to select a voltage when ordering): 7v, 8v, and 9v. If you are looking for a lower voltage setup then take a look at our 6v setups and if you are wanting a higher voltage setup then take a look at our 12v pre-wired LEDs that go up to 15v.