Eliminates any (and I do mean A.N.Y.) sound of plosives or wind, no matter how hard the wind is or how close you are to a mic! Has three layers of foam total, the inner of which seems to be some sort of big celled mesh. The impact on sound quality is negligible (if at all present).
Bought it for samson Q2U headless mod, and the fit is a little snug, but it did fit in the end. The only complaint is the price, and the fact that they do not make similar products for side adressed microphones, but if you can spare the cost, it is worth it!