CRU means the part is a Customer Replaceable Unit.
hard drive means Hard Disk Drive.
Where the hard drive is not supported as an upgrade to the primary system hard drive, the option hard drive is supported as a secondary hard drive in the following:
48GB hard drive Note: Not supported as an upgrade to the primary system hard drive on the ThinkPad A series (2655 models), ThinkPad X series, ThinkPad R series, and ThinkPad T30 systems with the UltraNav touch pad.
08K9600
08K9599
Yes
60GB hard drive Note: Not supported as an upgrade to the primary system hard drive on the ThinkPad A series (2655 models), ThinkPad X series, ThinkPad R series, and ThinkPad T30 systems with the UltraNav touch pad.
08K9688
08K9700
Yes
60GB hard drive Note: Currently shipping in the ThinkPad T30 systems 9.5mm 4200 rpm