I have a round protractor type thingy that has 360 deg on it and a slide that will rotate around to certain angle so you can check it.
That doesnt make much sense...the slide has a line on it and the whole thing is transparent...i look through it down on my mics to check the angle.
it prolly has a 3inch diameter.
i got it in a drawing kit in the school supplies in walmart for 3 bucks
and i have a seamstresses rules/measuring tape that rolls up into nothing...make sure it has metric on it, the first couple i found didnt
bush:smoking2:
edit---I was really suprised when i started using these how far off i was setting up my mics as opposed to how they were supposed to be