The 5000 Series consists of a popular industrial styled Lexan case that has a gasket for harsh environmental applications which seal out dust and other air-suspended damaging particles. A Nema 4 external gasket is optional. This Series is available with optional stud placement configurations for panel interchangeability. This built-in interchangeability eliminates the need for panel changes, setups and redressing of panels... it solves your instrument replacement problems.