In 2013, Steven Seidenberg encountered the pipevalves (in German,Reinigungsäffnung) depicted in this volume on daily walks around the neighborhood in which he was based during a residency in Berlin. He was hooked at once by their totemic quality, and he first photographed the two located on the same block as his studio. As he walked in and beyond the neighborhood he realized that the structures were concentrated within an area measuring just over .5 square km. Across most of Berlin, the cast-iron fittings photographed in this series have largely disappeared—replaced by plastic and aluminum plates throughout the East Berlin neighborhoods where they were once prevalent.