... configurations: ThinkPad T420, T420s, and T520 with "ThinkPad Mini Dock Plus Series (4338)" ThinkPad T420, T420s, T520 ThinkPad Display (1920 x 108 0) ThinkPad VGA (2048 x 1600) ThinkPad Mini Dock Plus Series ... configurations: ThinkPad T420, T420s, and T520 Dual Core with "ThinkPad Mini Dock Series (4337)" ThinkPad T420, T420s, T520 Dual Core ThinkPad Display (1920 x 108 0) ThinkPad VGA (2048 x 1600) ThinkPad ... configurations: ThinkPad T420, T420s, T520, and W520 with "ThinkPad Mini Dock Plus Series (4338)" ThinkPad T420, T420s, T520, W520 ThinkPad Display (1920 x 108 0) ThinkPad VGA (2048 x 1600) ThinkPad...