Microsoft Wheelmouse (Ball) Grudgingly still works and in perfect condition. Rollers need to be cleaned. PS/2 only. Microsoft Intellimouse Explorer 3 (Optical) LMB doubleclicks on a click. Microsoft Intellimouse Explorer 4 (Optical) LMB & RMB often doesn't register a click and must be pressed hard. Wireless Laser Mouse 6000 (Laser) Exterior is literally falling apart. Rubber of mousewheel flaking off. Natural Wireless Laser Mouse 6000 (Laser) The normally loose mousewheel gets stiff.