Lenovo T420i manual Step, Screw quantity, Color, Torque

Step	Screw (quantity)	Color	Torque
	M2 × 3 mm, wafer-head, nylon-coated (1)	Black	0.181 Nm
3
			(1.85 kgfcm)
	Shoulder screw (2)	Silver	0.181 Nm
4
			(1.85 kgfcm)

84ThinkPad T420 and T420i Hardware Maintenance Manual