Trackpad used on MacBook Pro Unibody 15".
Used on:
Mid 2009 15" Unibody MacBook Pro
Mid 2010 15" Unibody MacBook Pro
Early 2011 15" Unibody MacBook Pro
Late 2011 15" Unibody MacBook Pro
Mid 2012 15" Unibody MacBook Pro
Apple Reference: 922-9035, 922-9306, 922-9749