A Layer 2 network switch fabric is partitionable into a plurality of virtual fabrics. The camera carrier is connected to a firearm barrel, or removably attachable to the firearm. The wetting layer has a first wetting ability with respect to a surface of the substrate and the second layer has a second wetting ability with respect to the surface of said substrate. The concentration of the chemical component within the reaction solution is modified, during the reaction process, when the detected concentration value is different from the predefined threshold concentration level or different from the predefined concentration range.