Lenovo T420 - Manual (Page 113)

3 M2 × 8 mm, wafer-head, nylon-coated (2) Black 0.181 Nm
(1.85 kgfcm)
4 Hex stud, nylon-coated (2) Silver 0.392 Nm
(4.0 kgfcm)
Chapter 8 . Removing and replacing a FRU 107