DerBlue Aluminum Trumpet Practice Mute, Straight 1. Size: Length: 15.5 cm6.1in; Diameter of Small End: 2.8cm(1.1in); Diameter of Larger End: 9 cm(3.5in) 2. Fit all type trumpets,Made of excellent aluminum and Premium neoprene-enhanced composite cork pads for long-lasting usedurable for use 3. Very useful when you feel like playing your mute in the middle of the night - Your family members, neighbours and pets will be glad you purchased this 4. It produces the type of sound that is considered the "standard" in cup mutes, for most jazz musicians 5. If you grease the cork when use the mute, the trumpet practice mute will get fixed to the bell much easier. The oil can also save the cork from crumbling, so we suggest you to grease the cork regularly