From the project website (accessed 2019-10-31):
Krateros is the digital repository for the collections of epigraphic squeezes at the Institute for Advanced Study (Princeton). The squeezes, which are three-dimensional, mirror image impressions of inscriptions, were created and donated to the Institute by the Epigraphical Museum in Athens and some of the greatest epigraphers of the twentieth century, including Louis Robert, Charles Edson, Sterling Dow, and David Moore Robinson. Stephen Tracy, Professor Emeritus of the Ohio State University and former Director of the American School of Classical Studies at Athens, has written an introductory primer on the squeeze collection, and Christian Habicht, the late Professor of Ancient History at the Institute, has provided an overview of the Origin and Development of the squeeze collection. The digitization project is funded with generous gifts by the Charles and Lisa Simonyi Fund for Arts and Sciences and the Fowler Merle-Smith Family Trust.</p>
The digitization of these squeezes is a work in progress, and thus new items will regularly be uploaded. The team’s current focus is on squeezes pertaining to Inscriptiones Graecae Volume II, second edition, i.e., IG II(2). These squeezes will be uploaded in more or less ascending order by their IG II(2) number.