This SLR Magic Variable ND Filter Mark II is specially designed to minimize the weird uneven vignetting that sometimes afflicts variable filters. How? Using "special glass and treatment." Not sure what that means, but it seems to do a pretty good job. ND range is from 0.4 to 1.8 (just over 1 stop to about 6). A bit bulky- it's thick, and the outer thread is 86mm- but this filter includes its own lens cap to make up for at least the last bit of that. In excellent condition.