Shure A81WS / Movo WST100 comparison-
I received a Movo WST100 yesterday. Externally, it is almost exactly the size as the Shure A81WS (aka Shure big ass wind screen), maybe a centimeter longer. Internal depth is quite different however. The Movo is 4" (100mm) deep while the Shure is 2.5" (65mm) deep. Difference is due to the Shure having a thicker piece of internal large-cell foam at the front end of the windscreen, preventing insertion of the mic as far as it can be inserted into the Movo. The Shure design helps keep the mic diaphragm properly centered in the windscreen. With the Movo one can insert the mic farther, but shouldn't if looking for best wind noise reduction performance, as there would then be considerably less less dead air space at the end of the mic, on-axis directly in front of the diaphragm, than there is out toward the sides.
This may explain the Movo not working as well as it can for some folks. When using them in very windy conditions don't push them on as far as they will go, but rather only so far as to achieve about the same thickness of windscreen all around the capsule. [edit- or rather, somewhat more in front than the sides. The Shure encapsulates substantially more dead air space in the front than the sides, something like twice as much. That kind of distribution is something commonly seen in the design of slip on foam windscreens, and something I've always wondered about]
The tl;dr- in the Movo lineup it appears that the number following WST is the intended insertion depth in millimeters.. yet one can insert the mic farther if needed, likely the risk of less wind noise suppression.