Size I guess, others cover the wheel and generally cover the lower end of the bike. This one looks like it would stick above the bike and is designed more for stopping bugs from smashing in to your face then to improve aerodynamics.
Since you seem to be an expert at this, you tell me why you think this one provides the same benefits as the the ones you posted?
I don't claim to be an expert any more than you appear to be. Do you see any difference in what I'm saying and what you are saying?
The size differnce you said? It's a "mini windshield" 9" 3/4 wide, 13" 3/4 high. Much smaller than ones in zzipper.com. If for any reason it is less efficient than zzipper, it would be beause it's smaller. In any case, it's still better than catching the wind in the body.