I've been checking these last month. Some sellers sell their fake iem by adding DIY at the end. So you can easily find Sennheiser + model + diy.
It looks like they found a decent sound quality usually targeting harman curve and selling it that way. And all those people giving positive comments is coming from the harman target's likeable nature.
However, there are some malicious sellers out there straight putting the ads as original Sennheiser. And there are ofc those people buying and leaving positive comments.
They're really good at replicas and this has been for many years for the products like Sennheiser, Sony even Audio Technica.
With the packaging everything they get very very close and you have to put an original next to it in order to point out that differences.
Usually it used to be workmanship. Like fake ones having some remaining glue, plastic at the edges. Then it follows with slight color differences, text texture and spelling mistakes.
However, for a newbie it's hard to understand that as they can't afford to buy the actual one. So, it's like win win. You buy a Sennheiser ie900 with 60-70% discount with all those accessories very similar to the original.
Take this with a pinch of salt but I belive they take a good DD in the market from a manufacturer and putting inside these shells. I believe it'd cost around 50 normally if it wasn't sold that way. Very good job though.
I've seen one seller put one like that. I went their history and it showed me that they were selling fake jbl speakers. However, they screwed these up big time that letters were falling off, the side passive drivers were not strong enough to hold the pressure so they were exploding. I don't even count battery, sound quality and water resistance issues.
This is important. What shocks me the most and makes me double check each time sth on AE that they let this seller exist! After all those negative comments. So the seller removed all Jbl products. Switched from a so called official Jbl seller to Sennheiser sellers.
That makes you think. Maybe I should buy and prove that it's fake. Well good luck. I saw comments that people's refund claims were rejected or they got amounts like 2$. Joke right? AE will never gain my trust because of these.
Avoid at all costs...