Size 6 to include the gap of 0.75" Bandwidth is 0.625" Collected from the original family who collected this in the 1920-30s in the Monument Valley area. Sidney Pockels was co-owner of Pockels, Paint, and Glass Company. Sidney, frequently climbed into his model A Ford to travel from Saint Louis to the Monument Valley Navajo Indian Reservation located at the Arizona/Utah border. It was here that he was continually drawn to witness the wonders of the Navajo Indian festivals and artistry. The family always thought that Sidney never married because hed rather be in Monument Valley then at home. This was purchased here by Sidney and passed down through his family since his death in 1955.