The light emitted from the LEDs is quite bright. The thin blue piece of plastic included in the kit makes the arc reactor emit a bluish-white light. There’s so light leakage through the coils or copper wires.
Strangely I was left with some provided tools which I did not use. The electrical insulating tape was left untouched, as was the quick-dry putty and permanent silver marker. I’m guessing the putty is so fixing any breakages along your build, and the silver marker can be used to colour in some of exposed clear acrylic so there’s less light leakage.
This DIY arc reactor is very impressive. For HK$240 (USD $30), it makes an ideal addition to a mod or cosplay outfit.