The ideal choice for any musical genre the Jo-Ral Bass Trombone Straight Mute produces a smooth distinct tone It is free-blowing in all registers and designed to fit all tenor trombone bells. The Jo-Ral TRB-4A Bass Trombone Straight Mute made of spun aluminum and has been tested to perform evenly in all registers. Jo-Ral mutes also feature neoprene-enhanced composite cork pads that provide extra durability. The result is a more pliable cork that grips well and doesn t dry out become brittle or break off-so it lasts longer while easily accommodating fine adjustments for a perfect fit. Features: • Fits bass trombones • Crafted from lightweight spun aluminum • Smooth distinctive tone • Pliable neoprene-enhanced composite cork pads offer lasting durability and grip • Soft felt cap for extra protection • Made in the USA