Pretty sure that could just be a venting port. Almost all IEMs have them, just smaller ones. They help relieve pressure build up in the ear and prevent driver flex.

I mean, you can see it for yourself. Term "open-back" is not something that exists in IEM world, even iSine is called semi-open. This is nowhere near iSine level of openness

Well, I wonder why they decided to make the vent so large though. It does lead to sound leakage.

looks like cooler version of normal vent to me

What about Raptgo Hook X

Eww, put it back

I dunu?

That’s the closest you’re going to get. Using them on discord / for calls is really nice because the occlusion effect isn’t as prominent. I’d have kept mine if the comfort was better. But they’re still in ears and they block a lot of sound compared to open back headphones or earbuds.

real vent(filter) is glued to the driver, vent on the shell is just decoration

This is incorrect, rear vents on iems is a significant tuning choice. Yes, There is a resistance element glued to the rear of the driver, but sealing Vs leaking the housing has a dramatic effect. Rear loading a driver and venting the rear cavity are entirely different things