Anyone who does video work would have come across wind passing over a microphone causing an annoying wind noise.
Below shows a Sennheiser MKE400 mounted on top of a Panasonic HC-X-900M camcorder without any wind blockers on the external or built in mike.
As you can guess absolutely useless like this, so Sennheiser proved a foam wind blocker
had no real affect so I purchased one of these (no its not a skinned mole but the fur is about the same length)
Slight improvement but not really up to the job so next purchase was
So how did this perform? At a rough guess it cut out about 80% of wind noise and about the best performance muffler I could find. it slips over the Sennheiser muffler easily
So saving anyone thinking about stopping wind noise using an external mike the best is with the longest fur possible
Hope this may be of interest. Oh by the way that is a superb small mike but does cost a bit, but worth every penny.
Mounted on a Nikon D800 to give idea of size