I have a handheld scanner that looks exactly the same, sold under the Trust brand, it's a 256 grayscale model, forgot its exact name.
I have the 5 floppies that came with it, the DOS/Win3.x drivers and scanning tool, Image-In, a scanning/editing/OCR software in French and Perceive Personal, an OCR software in English.
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It definitely supports Twain, there's a Twain.dll in the scanner drivers/utils directory.
If you google around, you can find an old DOS version of Perceive Personal, in case you want to try your scanner in DOS only.