It's a pretty cool cosmetic thing you can put on your blaster. I decided to put the 2 I bought on my nemisis hopper, and looks pretty cool. If you put enough power through it, you could probably stuff like 5-6 of these in a blaster with a thin she'll, cause the lights are strong enough to kinda go through plastic. My only complaint is that the tape that's mean to hold the lights to what ever you put them on isn't sticky enough, so I used super glue.
This light works and moves beautifully. It can be powered off of a 9V and I would not recommend anything lower than that. Between a 9V and 9.6V NiMH you will notice a major difference. These lights really shine when you use the proper voltage. Just make note of how big of a battery you can fit in your blaster.