"of Enchanting" Suffix mod question

Is it enchantments that YOU cast last longer or enchantments that are cast ON you, or enchantments that you cast on YOURSELF? I'm kidna confused...Help please?

It's enchantments that you cast, either on yourself or others.

i don't think it matters any enchantment cast on you or anything it will last that much longer dosen't matter

This isn't correct, the first responder has it right.

It only effects enchantments you cast while holding the weapon.

Ok, Thanks