KRNTR Trombone KTR-30 "Metallic Red" It is. The piston bottom cap and piston buttons have been changed to a heavy-type specification. Of course, it can also be switched to the original normal type. The metallic red and heavy-type specifications provide a tremendous visual impact. It looks great for solos on stage, as well as when switching instruments on the spot. It is not new, but it is clean with almost no signs of use.