This is by far the best playing King 4b I have ever played
The slide was made specifically for John Marcellus
This slide has a removable lead pipe
Conn-Selmer says this about the King 4b:
"The King 4B trombone has a classic large bore symphonic trombone design. Because of the .547 bore, it has a very open feel and is best suited for the lower parts in a jazz band as well as for symphonic playing. This is a very versatile model of the trombone. A bronze brass bell comes standard on this model to offer the performer a quick response and a warmer tone. "