Ultra

I've got a level 50 tank that I'm having trouble getting his damge resistance and Defenses right. He does a good deal amount of damage but can't take as much as i'd like him to. all of his damage resist powers have 5 enhancements slots with Aegis with a couple with titantium coating. all level 50 and i i have a ll of th defense sets with luck of the gambler. Are these the best slots enhancements i can get or is there something that could help my defense and damage resistance out?