Top positive review
This is a LOW ENERGY BLUETOOTH (BLE) dongle
Reviewed in the United States on June 10, 2020
The most important thing to note here is that this version is Low Energy Bluetooth.
What is Low Energy? Well it's a Bluetooth receiver designed specifically to receive signals from Low Energy Devices. Many devices (cell phones, heart rate monitors, proximity sensors, fitness devices, etc.) have strict guidelines with power consumption and therefore use BLE.
Both regular (Classic) Bluetooth and Bluetooth Low Energy can scan for other Bluetooth devices, query the local Bluetooth adapter for paired Bluetooth devices, establish RFCOMM channels, connect to other devices through service discovery, transfer data to and from other devices, and manage multiple connections.
Classic Bluetooth is the right choice for more battery-intensive operations, which include streaming and communicating between Android devices. For Bluetooth devices with low power requirements, those using Android 4.3 with application programming interface of 18 (API 18) supports Bluetooth Low Energy. But all the technical mumbo jumbo aside, make sure you select the correct type of Bluetooth Receiver for your requirement.
If you want to move mass amounts of data (like streaming video), regular Bluetooth is better.
If you have low energy devices that use API 18, you'll need a Low Energy Bluetooth receiver like this one.
Functionally, there's not much to these. The Bluetooth version is 4.0 (they're up to 5.0 now) which is more than sufficient for most peoples needs (the latest version has improved processing and greater distance range). These devices are relatively inexpensive, and they turn your non-Bluetooth device instantly to a Bluetooth one.