The .part3.rar extension confirms this is the third piece. It cannot be extracted alone.
This indicates that a larger file or a collection of files (possibly an image of an SD card, a compressed backup, or data intended for an SD card) has been split into at least three smaller parts (.part1.rar, .part2.rar, .part3.rar) to make transferring, uploading, or downloading them easier. What is this file? SD Card 256mb.part3.rar
The "256mb" in the name likely implies the total content, when fully extracted, is 256 Megabytes. How to Use This File To access the contents, you must have all the parts ( , etc.) in the same folder. What is this file
Use WinRAR or 7-Zip to open the first file (part1). Use WinRAR or 7-Zip to open the first file (part1)
Based on the file naming convention, is a segment of a multi-part RAR archive .