Material: Metal. Rubber rings are dismountable, durable, and long service life. Exercise lip muscle endurance. Practice mouth strength and fix mouth shape. Use both ends; pull one end to exercise lip biting force and lip muscle strength concentration. One end is designed to be held like a pencil for 10-20 seconds at a time. Applicable for trumpet, trombone, cornet, clarinet, saxophone, and horn. This trumpet mouth exerciser works on the principle of trumpet mouth and breath forward, lip concentration, and mouth closing. It helps avoid pulling out the corners of the lips, practices gum and teeth closing, improves teeth alignment and lips parallelism, and corrects mouth shape and breath during vigorous practice. It is recommended not to use it immediately before playing, as the exercise may cause fatigue. Specification: Material: Stainless steel Color: Silver/Gold Item size: 65 x 18 x 10mm / 2.6 x 0.7 x 0.4in Package weight: 38g / 1.4 ounce Package Includes: 1 x Mouth Strength Trainer