Hardware & Technical PWM fan splitter. Help needed.

[Caramel Clown]

So I'm trying to plug in two 4-pin PWM fans into one header on my motherboard. "No problem" they said, "get a Y-splitter" they said. And I did. However, there seems to be some kind of incompatibility problem I wasn't aware of.
Male ports on splitter seems to be the right amount of pins for fan connectors, but their sleeve has those grooves to apparently secure connection. Only one thing - they don't match. How...what? Why? Are there different kinds of PWM connectors around? Also, one of the inputs on the splitter is full 4 pins while other has 1 pin and wire missing. I'm starting to think those are purely for CPU fans, which I didn't realize may have different 4-pin connectors.

Spoiler

 

[AkenBosch]

Yep, that doesn't look like a PWM, and definitely not a PWM splitter if one of the inputs has only three pins. 4-pin PWMs use the same grooves of 3-pins, with the fourth added on one of the sides. What you need should look like this:

Spoiler

 

[Caramel Clown]

Yep, that doesn't look like a PWM, and definitely not a PWM splitter if one of the inputs has only three pins. 4-pin PWMs use the same grooves of 3-pins, with the fourth added on one of the sides. What you need should look like this:

Spoiler

https://www.kenable.co.uk/images/006339_m.jpg

It looks like this. Only one of the split signals has 1 wire and 1 pin missing. I already guess it's for CPU twin fan coolers, which don't need separate controls. Also, those grooves on the connectors don't match. Ones in your pic look different, and would fit my fan connectors. I guess I've just got a useless thing, one more piece in a box of various hardware and cables that is quite honestly too full of stuff I have no need for Oh well, at least it was dirt cheap. Ketchup and mustard cables...another good reason to get another one, with a sleeve.