I have tested this windshield and it works accordingly to the expectations (I haven't used it in extreme conditions yet).
I am only concerned with one thing: using it with an Sennheiser MKH418S it does not feel like a good fit. It is a little bit harsh on the mic while pulling it in/out. The interior of the product is not soft at all, it's a harsh/hard plastic net, with pointy pieces of plastic all the way trough. As a result this plastic material gets stuck in the microphone grill and I'm afraid it might damage it.