If you are looking for the Buffalo Bluetooth 4.0 USB adapter then you will find it listed below. Note that this was the last driver for this adpater which was in 2011. This should still work today even though the driver is rather dated. The operating system for which it was made is the Windows 7 (32bit / 64bit) / Vista (32bit / 64bit) / XP SP3 or later. This is still good now unless you wish to run it on Windows 10 which might be a problem.
The Buffalo dongle is for the BSHSBD04 / 05/08 which is still made in Japan. You can download and install this file below.