A Keilmesser is a German classification for Micoquien, the stone tools created by Neolithic peoples. Keilmesser tools are backed stone knives created by flaking off shards of stone to create sharpened edges, typically on both sides of the tool. This Keilmesser was excavated from a neolithic site in Byzovaya, in the western foothills of Russia’s Polar Ural mountains. The site has been carbon dated to between 29,000 and 32,000 BCE, and is theorized to be one of the last refuges for the Neandertals, before they were driven to extinction by Homo sapiens.
Reed Enger, "Keilmesser Stone Tool," in Obelisk Art History, Published October 25, 2016; last modified August 01, 2021, http://arthistoryproject.com/timeline/prehistory/paleolithic/keilmesser-neolithic-stone-tool/.