These are the most commonly used devices in an Outdoor Aerial Display, producing many different types of colors and effects. The most typical effect is the familiar round flower shell, but shells can also make patterns, produce salutes, and even deploy parachutes. Other types of special FX include crossettes, bees, willows, palm trees, mines, whistles, spinners, strobes and multi-break shells. Aerial Shells are fired from mortars secured in wooden racks and angled in various directions. Shells come in many various sizes, with diameters as small as 1/2 inch to as large as 36 inches, although the most commonly used shells range from 3” to 6”. In general, the larger the diameter the bigger the burst or spread, and the larger the safety zone needed.