Zero radius sinks were the first small radius sinks. The Zero Radius sinks had sharp corners which made them difficult to clean particularly in the bottom corners where the side corners and the bottom meet. The picture below shows the problem corner in the sink. The bottom picture shows the corners on the Cygnet Stainless Small Radius sinks. Both the Evolution Series and the PerfecFlo™ sinks have 3/8″ diameter corners. These small radiuses make the sink easier to clean and also stiffen the sink and make it quieter.