What is a TF card for a Bluetooth speaker?

In 2004, SanDisk and Toshiba collaborated to create this product You might have first seen one of these guys popped into the slot on the side

This video shows how to insert TF card of Pipo tablets

tf slot on bluetooth speaker A TF memory card, also known as a TransFlash memory card, officially rename as Micro SD Card since 2004, is a type of small, portable storage

tf slot TF and SD cards are commonly used memory cards for small electronic devices Yet most of us have heard about an SD card but usually not a TF