Basically an A3 scanner so 30cm (A3 short length, A4 long length)
But with the ASF on it it copies them in duplex in no time and will take larger than the A3 size long length which has been useful.
I have a couple just to check through before they get chopped into pages, and tidies up and uploaded (not GT though, early 90 Shimano, Suntour, no need for the 97 Saracen now but it's a better scan and I think a some '97 of others..)
The scanning is the quick and easy part.