I bought ChemWindows at the ACS meeting last spring and at the time I got MS Palate. It allows you to take a structure you have drawen with ChemWindows and see the fragments and masses as you bisect the molecule. It is a simple package but useful, I think. I don't do a lot of MS work but it seems to be useful. Jim Macmillan Department of Chemistry University of Northern Iowa macmillan |-at-| uni.edu