23.0mm Optics/Light Diffusers (PMMA/5-Pack)

Pros: nice cheap diffusers work well wit my cree q5 xres. the light is magnified a bit and appears brighter the light is also more focused and is in a horizontal beam or they can be turned for a vertical beam.

Cons: the build quality is ok. they needed some modification for my crees to fit in but i did that easily using a jet lighter!

Other: buy em theyre cheap and good quality good shipping too all came in perfect condition.

Pros: Give a good wide beam, mostly focused into a rectangular shape, which can be positioned (by rotating the lens) at any angle

Cons: Not sure what these are designed to fit, or how the other guy got these to fit his cree q5 neatly.... can easily be modified
Domed head

Other: buy, build *and modify to get to fit*, ride!

Pros: This lens performs a function that is otherwise hard to find: it focuses light into a line or rectangular shape. This is good for a bike light, were you want to be visible from front left and right but do not care much about being visible from above or below.

Cons: The lens needs some distance from the LED: approximately a centimeter between LED dome and the back of the holder. The problem is the holder then shields a lot of light. So it is better to use this lens without the holer.

Other: Use it to make a wide(r) beam.

Pros: It makes flashlight like car's fog light - wide beam in the horizontal direction and narrow in vertical. You can make own headlight by changing the regular diffuser of flashlight.

Cons: I remove lens from holder because it can not be fixed by 5 mm thread of flashlight's cap.

Other: Use it in bicycle headlight.