Invisible marks

Exploration Stage: Octopus Citadel
From: Mr. Black
Description: Violet's plan to replace the dog's collar must be perfect. She is very careful. If we do even the slightest sloppy job, she'll know it. We need to attach this bug to the collar as discreetly as possible. Okay, let's find a nano soldering iron.
Completed: Oh, you found a nano soldering iron. Let's quickly attach this wiretap directly to the chain part of the collar. The most important thing is to work carefully so as not to break the wiretap. This nano soldering iron is a very useful tool. When you stick things with it, it leaves no marks at all on the connection.