ProtoArc Wireless Trackball Mouse 2.4g Ergonomic Rollerball Mouse Rechargeable Bluetooth Computer Mice 3 Device Connection

My own readings, in pounds. The first point is the first reading I took; after that a point goes on only when a reading comes in 5% or more away from the one before it, which is why the gaps are uneven. The price above is a later reading that landed less than 5% from the last point, so it has no bar of its own.