Needed 2 speaker boxes for a piano upgrade. They hold a 1.57" speaker.
They require 2 pieces of .03" thick .08 round hole perforated stainless steel sheet 1.815" x 2.75" for the grills.
Mounting screws at #8-32 2" long+ I used 2-½ long but it will depend on what you mount them to.
The author hasn't provided the model origin yet.