The whole ram ways 3.5kgs, the rod is 20mm stainless rod. It is 63mm bore, 145mm stroke. So it weighs more than it needs to but better to be safe than sorry! The walls are about 6mm aluminium and the end caps are 30mm thick aluminium, its held togther by 8M6 tie rods all 2mm away from the wall of the tube- should do the job.

I don't know the weight of just the rod and plunger but can weight it tomorrow for you, why do you ask?