There are several types of plastic distribution box panel accessories available, each designed to fulfill specific functions within an electrical system. Common types include circuit breakers, switchgear, and distribution panels. Screw connection with nut, contents: 2 pcs. Screw connection with nut. The groove contours of electronic distribution boxes and the very narrow grooves of micro-distribution housings are seamlessly sealed with the sealing foams of the polyurethane-based FERMAPOR K31 or the silicone-based FERMASIL product families.