Bests & Worsts Reviews from Amazon

This device is exactly what it says it is: a Bluetooth 5.0 USB nano-dongle. It will work under Windows with the Techkey Driver Package, and despite not being officially supported, will also work under Linux with a modern kernel (5.8.2 or later) & some tweaking. The device is essentially a rebranded ASUS USB-BT500 bluetooth dongle. It works reasonably well - i get better range and performance out of it then any other Bluetooth 4.0 nano-dongle I own. The connection is more reliable, stable, and drops out less. It's not perfect - the range is about average, and it still has some connection issues from time to time. For $20, it's not a terrible deal if you're looking for a Bluetooth 5 receiver. So, about those drivers. Many reviewers have pointed out that Windows 10 doesn't require a driver for bluetooth devices. This is correct. However... This dongle along with its cousin, the BT500, uses an RTL8761b chip. The RTL8761b chip, like many other modern devices, rely on the operating system to push firmware to the device. (essentially the code that runs inside the device, which tells it how to operate). The firmware is not provided as of yet to Microsoft or the linux-firmware package. Therefore, Windows requires an external driver to push the firmware to the device. Thanks to Meghan in one of the other review comment threads, we know that the Techkey drivers are virtually identical to the BT-500 drivers. These drivers are properly signed by Realtek, so you can be reasonably certain that the drivers are safe to use. This is the same reason that the dongle is not 'supported' under MacOS or Linux. It is possible to get the device working on Linux by installing the firmware manually. (essentially, taking the 'rtl8761b_mp_chip_bt40_fm_asic_rom_patch_new.dll' from the drivers and installing it in /lib/firmware with a proper name & copying the config from the rtl8761a. use 'dmesg' when you connect the device for more information.) It is unlikely that this device will ever work under MacOS unless there's a way to load custom bluetooth firmware. This will, hopefully solve any confusion with this dongle. We can only hope that Realtek will release the firmware to the OS providers, so that this device will work without drivers on Windows and Linux.