All of the feasible external leakage details between the stem & gland flange, gland flange & system, and overall body & adapter are sealed which has a Key O-ring after which a secondary graphite gasket. The graphite packing rings are compressed and held in placement because of the gland flange, https://angelojzlyi.mappywiki.com/1450451/5_easy_facts_about_ss_flanges_described