ANNQ42'S PROFILE

I am sure this is something easy.

I am trying to do 2 things:
First I am trying to create a shield belt with a certain number of hit points to it. So enemies will damage the shield belt until it is destroyed, then will start subtracting hp. This can either be a item or a piece of armor.

Second, I am trying to create an item that when used, it will make the actor invincible for a certain number of attacks. A similar mechanic to AD&D stone skin.

For instance: I use the item, the actor can then get hit 5 times before the item wears off. I do not want misses to count towards the countdown of hits. If possible I would like this item to be persistent through battles.

Any help would be appreciated.
Thanks.