Smooth, rounded integral bushing in each hub to protect conductor insulationAccurately tapped, tapered NPT threads for tight, rigid joints and ground continuityRemovable nipple in male sealing fitting may be used interchangeably in top or bottom hubRestrict any explosion to the sealed off enclosureRequired in Class I, Division 1 and 2 locations within 18 in of enclosures containing apparatus that may cause arcs, sparks or high temperaturesRequired in Class I, Division 1 and 2 locations where 2 in or larger conduit enters enclosure, fitting housing terminals, splices or tapsRequired in Class I, Division 1 and 2 locations at the boundary where conduit leaves classified locationRequired in Class I, Division 1 and 2 locations where two or more enclosures are connected by 36 in or less conduit, seal must be located within 18 in of either enclosureRequired where cables which exceed rate of gas or vapor transmission permitted for seals are used in Class I, Division 2 locations25% fill vertical and horizontal conduit sealing fittings for close turning radius