The OL 4 is slightly larger in diameter than the 4.5 and offers similar distinctive sound qualities and easy access to the extremes of upper and low registers. Because it is slightly larger than the 4.5 it does tend to blend more into the low brass ensemble texture. -the manufacturer
• 25.9mm (1.020 inch) cup diameter
• 0.264 inch throat
• Light artist blank
• Medium depth cup
• Silver plated