IOs that give buffs when used

In auto powers they are always on. In toggle powers they stay active as long as the toggle is active, and 120 seconds after the toggle is turned off.

Technically, in a toggle or auto power, they are refreshing themselves every ten seconds, just like a proc, since all they are is procs with a 100% chance of firing.

To explain to the OP:

A proc is anything you see that has "Chance for" in it's name. Like Mako's Bite: Chance for Lethal Damage. Any time you use the power that has that enhancement slotted in it, it rolls on another table to see if that proc goes off. Usually the chance is 20%, so every time you attack with that power, you have a 20% chance to do extra lethal damage.

The Numina's Convalescence, Miracle, and Regenerative Tissue uniques are exactly the same thing, only their chance to fire is 100%. In a healing click power, such as Heal Other, if you have the Miracle unique slotted, there is a 100% chance of your recovering being buffed by 20% for 120 seconds, every time you use it.

Toggle powers and auto powers make checks every ten seconds for procs to fire. If you have a Performance Shifter: Chance for +End in Stamina, every 10 seconds it will make a check for the proc to fire, if it rolls under 20% on the randome number generator, the proc goes off and you gain endurance.

The Miracle proc slotted in Health behaves the same way, only the chance is 100% instead of 20%. So every 10 seconds, it makes a check to see if the proc fires, and since the proc cannot fail to fire, it applies the buff.

Originally Posted by Dechs Kaison See, it's gems like these that make me check Claws' post history every once in a while to make sure I haven't missed anything good lately.

Just to add to the above posts, the Paragon wiki has a table of all the types of Special Invention Origin enhancements,and how they work:

http://wiki.cohtitan.com/wiki/Table_of_Special_IOs