Brass instrument Brass instrument A brass instrument is a musical instrument that produces sound by sympathetic vibration of air in a tubular resonator in sympathy with the vibration of the player's lips. Brass instruments are also called "labrosones", literally meaning "lip-vibrated instruments". There are several factors involved in producing different pitches on a brass instrument. Slides, valves, crooks (though they are rarely used today), or keys are used to change vibratory length of tubing, thus changing the available harmonic series, while the player's embouchure, lip tension and air flow serve to select the specific harmonic produced from the available series. The view
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