Abstract: A poke through fitting comprising a conduit body, the conduit body including a conduit, a fixed flange and a slidable flange, and an intumescent member formed at least in part of an intumescent material, said intumescent member comprising a retention member for retaining the intumescent member on the conduit body wherein an engagement member maintains a relationship between the slidable flange of the conduit body and the intumescent member during expansion of the intumescent material. A stop member is preferably provided in a fixed relationship to the conduit to limit the travel of the slidable flange during expansion of the intumescent material.