Open a new part document.
Open a sketch on the Front plane.
Beginning at the origin, sketch a vertical line upwards and dimension it to 60 mm in length.
Click Extruded
Boss/Base 
on
the Features toolbar.
In the PropertyManager:
Under Direction 1:
Select Mid Plane in End Condition.
Set Depth
to 120.Under Thin Feature:
Select One-Direction in Type.
Set Thickness
to 5.
Click OK
.
