The Mercurytm is an entry level ball energized by the newly designed Orbitertm core. This high RG low differential weight block delivers increased rev rate in the mid lane along with smooth continuation down the lane.Encapsulating this new power plant is the always successful Sure Grip IItm pearlized reactive coverstock. This mild reactive blend gives you fluid acceleration through the heads and dependable backend motion through the pins. ROTO GRIPs PRO PIN technology is taking layouts and ball reaction to the extreme. Once only used on the Professional Tour for condition specific drillings, these balls are now being made available in limited quantities to the general bowling public. Why As the requests, requirements, and styles of today's bowler changes to address new lane conditions and patterns, STORM is answering by providing and packaging these items separately from the standard first run items due to their unique nature and value.ROTO GRIP PRO PIN bowling balls are All first quality ROTO GRIP bowling balls Manufactured with the same high quality standards as all other ROTO GRIP products Manufactured with the highest integrity Made with the same high quality materials as all other ROTO GRIP products Great for specialized layouts and drilling options Potential for enhancing dynamic use of core position Meet all A.B.C., U.S.B.C. and P.B.A. regulationsROTO GRIP PRO PIN bowling balls are first quality bowling balls with pin distances over 5 from the center of gravity and top weight between 2 and 4 ounces. Through our testing, we have found that these balls lend themselves to a variety of drilling patterns outside the range of pins less than 5 which would require an extra hole to accomplish with standard pin and top weight specificiations. Based on the desired reaction, some Pro Pin drillings may require an extra hole for balance requirements.Please visit your pro shop professional for assistance in determining the best layout for your style and