Lightest: 5 weight Armament & Industrial NanoLube, specially formulated for deep & fast penetration, some engineers have dubbed this formulation "WD40 on steroids", unlike WD40 which stands for "Water Displacement" basically help unfreeze parts & will evaporate after its duty, a minimal amount of WD40 stays behind.
The high concentration in Nano-Oil™ of the active ingredient called Nano-Bearings™ will stay in place after unfreezing oxidized (rusted) parts & components treated. In most cases such parts will actually function again: shafts in bushing - roller bearings - etc.
Parts treated should function for a long time, however common sense dictates replacing those failed parts in due time.
You can mix any of the 3 grades (5, 10 or 85) to obtain the viscosity of your choice