The extra reflective dots for Natural Point's TrackIR and SmartNav head mice give you 26 extra dots to use while interacting in games. Each sheet includes twenty 1/3" (7.5 mm) diameter dots and six 1/2" by 1/2" squares. Two sheets of dots ship per order.
For additional details, review the TrackIR 5
and all of the accessories, including the TrackClip Pro