Yes, you can make IEMs Wireless... With a "Bluetooth Adapter"

 IEMs, or "in-ear monitors", are basically in-ear high-end earphones, that usually look like this:

KZ ZEX hybrid IEM from KZ-Audio

Note the wires. Yes, this has wires. because these are wired IEMs. And most people prefer it that way. In fact, they would even upgrade the wires to monocrystal core, multi-strand, oxygen-free wiring... However, these wires are... replaceable. Yes, you can remove the wires. There are 3 types of plugs, 0.75mm (or 0.78mm), MMCX, and a new one called "S-plug", which seems to be a variation of the 2-pin. 

What if you want a set of wireless IEM? 

You could add on what's commonly called "Bluetooth adapter", or "Bluetooth upgrade wire". And they'd look something like this. This is the split version. You can also get one that's linked together via wire around back of neck. 

KZ AE01 BT 5.4 IEM Adapter via KZ-Audio

See where it connects to the two IEMs? So basically it will turn any 0.75mm or 0.78 mm 2-wire IEM into a Bluetooth wireless version. IEM itself is NOT included, but AE01 itself is available directly from KZ for as low as $25 USD or from Amazon in the US for about $34, which seems to be a bargain. KZ itself also makes a version using several different Qualcomm chipsets for different price points. And you can also find versions made for MMCX and S-plug. 

This obviously, is NOT the only company making such. Prices vary greatly, from $20 to $200. The more expensive ones are from famous maker (such as Shure) and/or using high-end Qualcomm Bluetooth chipset that also support Qualcomm HD audio, AptX, and so on. 

So if you have a good set of 2-wire IEMs, you can turn them wireless with these adapters. 

Not So Crap Stuff from China: Generic "F9" True Wireless Bluetooth Earbuds with Charging case (and acts as battery bank for other stuff)

This is only Bluetooth 5.0, so it's being sold as low as $4.99... with free shipping by Amazon via their outlet, Woot.com. They sold out, but they have a slightly better version also for $4.99 (claims to have better battery life?). You don't expect much for $5, and this overdeliver at $5. 

It can recharge itself from the case in about 30-60 minutes, and one full charge should lasts you at least 3-4 hours of non-stop play-time. And the case itself should be able to recharge the earbuds at least 4-6 times. And I'm being relatively conservative. Oh, and it claims to act as a small 2000 mAh powerbank and has a USB-A output port (it charges via the old-fashioned MicroUSB though). 

The fit is relatively comfortable once I got both buds fitted  properly. The eargel portion goes into the canal, then rotate the body until it fits into the crook of the ear. It won't stand up to rigorous exercise, but it should not fall off with walking or stair climbing. If you need them to be tighter, you need better eargels, which you can find on Amazon. But that introduces us to the nags and niggles. 

Now for the nags and niggles... this thing is very sensitive to the size of the eargels. Beware, that if your eargels are too large, your buds won't fit back into the case and may not recharge. I tried replacing the eargels with foam tips... Won't fit nicely back into the case, even with pressure on the main lid. Also, the indicators of charge are pretty much junk. When it's out of power, it shows 2 out 4 bars. And one side runs out of power first (though only by a few minutes). And 2000 mAh battery... Who uses that? 

Still, it's great value for a measly $5. It may not looks as clean as the Xiaomi Airpod clone, but at least this ain't a "homage". And no, I won't pay $100-200 for earbuds, not even if its Bose or Sony.