Shemagh's.

[Hawkeye]

I need a GOOD Shemagh for an upcoming class. Anyone have any good recommendations on a source? I've seen plenty around, but not sure which ones are decent and which ones are crap.

[militarymoron]

from those i've seen, the olive/black and sand/black ones tend to be better/thicker. the other colours tend to be made of thinner material (like black/white, red/white etc). here's one place to get them:
http://www.optactical.com/shemagh.html

here's another question - what are you going to use it for in the class? i know that some people recommend wearing one around the neck to protect it from hot brass, but it's a relatively bulky piece of clothing for that purpose alone with loose ends to contend with. if you're also going to use it has a headwrap, shooting mat etc, then i can see the utility. if it's just the neck, you might want to consider a simple neck gaiter instead - more compact, no loose ends etc. this one by massif is an awesome piece of kit - extremely comfortable, available in two weights, very versatile, and no loose ends to snag anywhere. expensive, but it's made of proprietary fire-resistant fabric.
http://massif.com/nomex_clothing/neck_gaiter.php

[Hawkeye]

MM, multiple uses. Neck warmer in cool weather, sun shade in the summer, brass deflector (getting tired of scars on my neck and back from burnt flesh), neck protection during FoF drills, head wrap, etc.

[Ross]

I've used one for sun protection on my neck and it works fine. I don't have the problems of too much material, but I have enough real estate to cover, so it works. It works great when you wet it down as well. Throwing it over your head does work against the sun and heat.

As a neck warmer, I'd go a different route. It's cotton, so it doesn't provide much insulation value and when it's wet, it provides none. It's worse to wear wet cotton than nothing at all in cold weather.

I like it though because it's so big, and there's plenty of things you can do with it.