Camdenboss din rail vented module kit components camdenboss cnmb4pc the camdenboss cover clear m4 cnmb4pc is a component that when chosen in combination can be used to assemble a custom designed din rail module box the resultant enclosures are perfect for a wide range of electrical and electronic projects available in various size combinations the enclosures fit 35mm din rail or direct surface mountthe modules are made up by choosing from a choice of enclosures standard solid top