the trackball in this thing be only 200 dpus . and it be a pain to browse window with it . and the keyboard require line of sight to the receiver . I mean it have to face the receiver straight on or it will not work ughhh . and the receiver have the activity light on even when i be not even touch the keyboard or trackball . I think that be eat up the battery . battery life be horrible . after 3 month of use , i have to struggle to move the cursor with the trackball . it be wear down even though i rarely use it because it be a pain . it be expensive too . I get feed up with it and throw it on the ground . do not buy it !!!!!