Two Custom Rare Items

I created a pair of rare items for my Heirs of Ruin Dark Sun campaign that the players won't get for three or four levels. As it typical for my games, they will "level up" along with the party should they keep them, gaining new abilities in a similar fashion to legacy items from 3rd Edition. 

Personally I'm not particularly concerned if they are balanced with other rare items. I like to give my players extra incentive to keep items like this, and by giving them a bit of extra oomph it should feel more rewarding if they get them (especially since in Dark Sun the enhancement bonuses do not really mean shit).