Help me here - "PWM" fan splitter with only 3 pins?

Netherspark

Reputable
Feb 11, 2016
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So I've just bought an Akasa PWM fan splitter, one of the connectors has 4pins as you would expect, but the other one only has 3 pins instead of 4. I'm not overly familliar with PWM, having previously stuck to 3pin manually controlled fans, but wouldn't this make it "non-PWM"?

At first I thought it was defective or broken, but the stock images from Akasa themselves also show only 3 pins on that connector...

See here:
https://images-na.ssl-images-amazon.com/images/I/61a%2Bq%2BkUKOL._SL1500_.jpg

What's going on here?