... input device in today's world market this wirelss mulltimedia keyboard with trackball is one of the most fashionable computers input ... world market,,which combines the 2.4GHz wireless radio frequency,optical trackball,two mouse keys and scroll wheel,it will bring you the ... (not included in package ), aroud 3 months endurance System Comatibility :Windows 95/98/Me/NT/2000/Xp/Vista/Win7 Energy saving ...