A 4G USB flash drive. The actual capacity is about 3.6-3.7G. 100000 words, if it is TXT. According to a word 2B, it is probably 1.9MB, but other formats are different. For PDF and the like, most of them are scanned versions in the form of pictures. Depending on the quality, clarity and size of the picture, the size is different. I don't know about that. If it is TXT, then 3.6* 1024=3686MB, divided by 1.9, is probably 1940. So the final result is about two thousand. I hope my answer can help you. -Dark Sun