Brass instrument the player of a brass instrument has direct control of the prime vibrator (the lips), brass instruments exploit the player's ability to select the harmonic at which the instrument's column of air vibrates. By making the instrument about twice as long as the equivalent woodwind instrument and starting with the second harmonic, players can get a good range of notes simply by varying the tension of their lips (see embouchure). Most brass instruments are fitted with a removable mouthpiece. Different shapes, sizes and styles of mouthpiece may be used to suit different embouchures, or to more easily produce certain tonal
Facial hair in the military will cover the upper lip line, extend sideways beyond a vertical line drawn upward from the corners of the mouth...or extend above a parallel line at the lowest portion of the nose." Those with skin conditions such as pseudofolliculitis barbae or severe acne are allowed to maintain short facial hair with the permission of a doctor or medic, but no shaping is allowed, only trimming with an electric razor, or approved regular razor. 1/8 - 1/4 of an inch (3.2 mm) is usually the standard for this condition. Additionally, for almost a decade, ending with a "deauthorization" order that took