Materia : Augmented Materia Melder : Key Item prevents losing everything?

[urhryu]

Quote from Producer Letter.
Players who have met certain requirements can obtain the more advanced ”augmented materia melder,” which allows the attachment of up to five pieces of materia per item. Players can never fail to attach the first piece of materia. However, the success rate progressively decreases with each subsequent piece of materia. A failed attempt to attach materia will result in the loss of all items involved in the process, barring the key item.

From what I interpret, there might be a key item which can help prevent the lost of gear when you try fusing the 2nd-5th materia.
It would be nice if we can get more info. on that tho.