The BBG Windshield is a low-profile ball-type wind diffuser for cylindrical microphones. The BBG Windshield is made of the same materials as the standard windshield and is fitted with a grommet that grips the microphone body. The microphone is pushed through the grommet, completely enclosing the mic capsule within the windshield.
Used it in the Himalayas in late November. Yes, it was super windy. No, I didn't hear any noise during capture. Worth the additional cost. Highly recommend.
The Windshield works just fine with the Windjammer! From my experience it is better if you have your windshield size 1mm bigger (not more) than the actual diameter of the mic. When diameters are the same, the BBG will fit, but if you need to put it on and off from time to time, it is better to get an extra millimeter to smoothen the operation. Will not affect the efficiency of wind reduction.