How much resistance got rare mobs with "resisting" tag?

How much resistance got rare mobs with resistance tag like "resisting lightning"? I got 30 penetration gem conductivity 40 and harvest mob reducing resistance and compare to rare with no tag/mod I barely scratch them.

Yeah, even at very low levels it's seems a bit high. All I had as a skil was Lightning Tendrals and was fighting in my very first lake map at level 5. I encountered a rare mob that had lightning resist and it took about 10 minutes to kill the damn thing. So I had no lightning penetration at all. I thought it may have had a huge amount of HP but it had no special properties that gave it extra HP.

It certainly seemed to have more resist than 75.