When a Specific Set of Armor gives the player a potion effect when worn. Maybe make a command to bind which potions on what armor, the armor must be a specific set, so not all Diamond Armor can have this effect only certain set of that armor, this will not be a global thing, it will be for a specific set/named armor! Also another request is for you to make for Bukkit/Spigot 1.7.9 R.0.2, Thanks! Sorry if this has been posted before, some didn't work and some just made the ability of the potion on every set of the specified armor.
We don't have enough information here, how do you want to achieve the specific armor? Do you want us to hold the armor in the hand and write a command in chat to give that set of armor an effect? This is not clear at all, you just tell us that we have to make it specific but how, I need more information, this is not enough at all.
Please provide more information as said by @dkfredebang You might get devs willing to help you out if you provide more info