Deity V-Mic D4 Duo: the perfect vlogging mic?

This is my review and tests of the Deity V Mic D4 Duo, an innovative compact microphone for camcorders, small mirrorless cameras and so on, aimed at vloggers I think. It has two tiny shotgun capsules, one facing forwards and the other facing backwards, so that you can pick up sound from in front of you as well as any commentary from behind as you film. Buy the Deity V-Mic here: https://geni.us/UKA_DeityVMic4Duo