The only ones i'm aware of are the 'Rhodius vision' range and everywhere i've seen 'em locally or otherwise they've been 'kin expensive. Google shopping will get you a few sources if you're feeling rich
They have them in the Leengate shops - Pennine welding near us - part of a franchise jobby i think. They have them on display at the counter at the Leeds branch.
Never used them myself. Any good?
You can certainly see through them... http://www.youtube.com/watch?v=uPDIhXMfAdo. Don't know how good they are as they've always been about 3 times the price of regular style quality discs whenever i've seen them. I can't see them being a revelation to use personally
I used one of these a few years back (free sample) they are a cracking idea for grinding out welds prior to polishing as you can see when to stop before over doing it. Problem is the cost.
Used one at work a couple of weeks back, was asked to field test it, now bearing in mind what I do, we use a lot of small od tube on wheelchair's, extend arm rests, outrig arm rests, rear set them. fab spreader bars for the push handles, you get the idea, now normally after dressing the welds, depending on if you dress them horizontally or longitudinally you get differing amounts of metal removal either side of the weld which ends up with you having to do more linishing work before repainting. After trying one of these out I was amazed at the lack of intrusion or metal removal either side of the weld there was, as being able to watch the weld removal as it happens is a great benefit in deciding the amount of pressure and also movement you put into it. I personally think there are a great improvement over the normal flap disc's and have advised the we carry on using them, I found a site today which is a damn site cheaper than any of the others I came across, if anyone is interested this is IT