Introducing Propel X™ reactive coverstock, the newest addition in Brunswick coverstock technology. Propel X™ features an enhanced pore structure to provide Xtra consistency from shot to shot and Xtra versatility on a wider variety of lane conditions. Mechanical Asymmetric Core Engineering. The M.A.C.E.™ medium RG core has three major benefi ts, medium RG core system for a breakpoint further down lane, High RG diff erential to increase backend traction and High RG asymmetric diff erential to quicken the response time to friction. The Wicked Siege combines the new Propel X™ coverstock and the M.A.C.E.™ medium RG core to produce a ball motion that is clean through the front, consistent in the midlane with a quick response to friction on the backend. With its consistency from shot to shot and versatility across the lane, the Wicked Siege will be the fi rst ball out of your bag and a new benchmark ball for Brunswick on medium to oily lane conditions. The Wicked Siege can be drilled using the standard drilling techniques developed for asymmetric bowling balls. The unique core shape of each Brunswick 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. The same drilling instructions can be used for 12and 13pound balls. This is because Brunswick uses a generic core shape with an RG diff erential that is close enough to the 1416 pound shape.