ECHO CALLS INC Open Water Duck Dark Green Single Reed Acrylic. These calls generate a ringing hail call that will attract ducks at several hundred yards yet they are also very ducky and blow soft when the ducks are in close. Specifications for ECHO CALLS INC 77764 Open Water Duck Dark Green Single Reed Acrylic: Manufacturer: Echo Calls Color: Dark Green Fabric/Material: Acrylic Species: Duck ECHO CALLS INC 77764 Open Water Duck Dark Green Single Reed Acrylic