formula is halved; for no-value winds, no minute of angle correction in windage is required. Multiple flags are required for two reasons. First, the wind speed closest to the midpoint of the range has the greatest effect on the projectile. In addition, the wind at one part of the range will not always be the same at another part. Wind flags are not always actual flags, sometimes streamers are used, small triangle flags, or even pinwheels. Factors such as the range length and expected strength of the wind determine the best type of flag to use. When no flags are available, a small leaf or another small light object can be dropped from shoulder height, and the object is then pointed at by the shooter; the angle between his arm and his torso can provide an equivalent wind speed estimation as a wind flag, although it will not be at the mid-range location along the bullet's trajectory. Lighting Lighting should be consistent in intensity, glare-free, and shadow-free. The shooter's vision down range should not be obstructed by lighting behind the firing line. The illumination should be bright enough to prevent pupil dilation, which lowers the shooter's visual acuity. Emergency lights for egress, "Range in Use" signs at the entrance, and exit lights are among the other lighting options. During repairs or cleaning, the lighting behind the bullet trap should be at least 30 foot-candles. Common safety practices Although some ranges require all weapons to be discharged, securely encased, and/or trigger-locked before entering or exiting the facility, others do not. Many jurisdictions have no such restrictions, regardless of whether one has a concealed carry license in jurisdictions where concealed carry is legal. Whether indoors or outdoors, all shooters are typically required to wear eye protection as well as hearing protection (ear muffs or earplugs) at all times when within the defined boundaries of the range. Employees and users are exposed to lead dust from bullets or cartridge primers, which can be inhaled or can settle on skin or clothing. Additionally, the discharging of firearms in indoor ranges can produce noise levels of over 140 dB sound pressure level. To combat this, it is commonly recommended that those inside the range "double-up" ear protection by using both earplugs and over-the-head earmuffs, and to protect range bystanders from sound exposure. Depending on the range, prescription eyeglasses may qualify as eye protection. Indoor ranges