The Aura™ Mystic features the new Optimum Versatility Reactive Coverstock that provides more length and more backend reaction to achieve ultimate versatility. Finished with Rough Buff polish, the Aura™ Mystic slips through the front with ease, revving fast in the midlane and generating an extremely high angular velocity on medium to heavy oil lane conditions. The Aura™ Ultra Low RG core features a single density roundedoff elliptical inner core. The core is dynamically designed to extend the rotational energy, boosting angular velocity to transfer energy to the pins for increased pin action and higher scores. The Aura™ Mystic can be drilled using the standard drilling techniques developed for asymmetric bowling balls. At Brunswick, the unique core shape of each individual ball is used for weights from 14 to 16 pounds. This approach to lightweight ball engineering provides bowlers with consistent ball reaction characteristics across this weight range. At 12 and 13 pounds, Brunswick uses a generic core shape with a RGdifferential that is close enough to the 14 to 16 pound shape so the same drilling instructions can be used.