Lenovo ThinkPad T420 Hardware Maintenance Manual page 110

Step Screw (quantity)
M2 × 3 mm, wafer-head, nylon-coated (1)
7
Note: Applying labels to the base cover
The new base cover FRU is shipped with a kit containing labels of several kinds.
When you replace the base cover, you need to apply the following label:
Homologation label
17
The following labels need to be peeled off from the old base cover, and need to be put on the new base cover.
Note: If the COA label
the customer, or provide a letter to the customer stating what the label was originally on the system and
what the label part number, serial number, and product key were.
Windows Certiicate of Authentication label (COA)
1
Wireless LAN MAC address label
2
Information label
3
Ethernet MAC address label
4
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ThinkPad T420 and T420i Hardware Maintenance Manual
is attached to a part that is replaced, return the old part with the label attached to
1
Color Torque
Black 0.181 Nm
(1.85 kgfcm)