The Kinetic weapon was just his bead bracelet that he had been bringing along but never got the chance to use.
It was a level 3 technology, so it would be impossible to produce. But he still got the information he needed.
There was no need to worry much about the material since the Extreme Printer could just materialize it.
But he did not plan to mass produce the thing.
He printed only two copies to give Aria and Lucy to protect themselves.
Bell had already told him that they had their own means of protecting themselves, but it wouldn't hurt to give them something.
And thanks to their programming, even if the weapon was of little use to them, it was bound to make them ecstatic.
Even Lucy who was more aware of the situation would still feel the same. It could not be helped. Everything was to ensure that they remained loyal to him and served him to the best of their abilities.
And Lu Fan was honestly fine with that.