Sierra's INFINITY Exterior Ballistic Computer Software version 7 provides multiple trajectory charts and graphics, point blank range, calculate zero, uphill/downhill shooting, maximum range, minute of angle, profiled wind, improved atmospherics, revised print formats trajectory in mils and more. Easy to use Windows format makes INFINITY extremely user friendly. Bullet library includes all major bullet companies as well as ammunition companies and allows for addition of new and custom bullets. Renowned Sierra Ballistic Consultants Ted Almgren and Dr. Bill McDonald, who have written all Sierra Software since 1970, also wrote INFINITY 7. Both are retired Chief Scientists from a major aer Mfg: Sierra Bullets SPECS: System requirements are: WindowsA(R) XP, Vista, 7, or 8, 800x600 resolution, and 120MB hard drive space.