Hi, may I know what does the H1, H2... H11 stands for? Is it for the brightness, watt or size?

I am looking for replacement bulb for my Satria Neo. Which one do you recommend?

And do I need additional modification to use this? I am using the original bulb now.

sorry noob here

This post has been edited by orange256: Jun 8 2011, 01:28 PM