This explosionproof, dust-ignitionproof flexible coupling is for use with threaded rigid metal conduit and IMC. A smooth, rounded integral bushing in each hub protects conductor insulation. The accurately tapped, tapered threads provide tight, rigid joints and ground continuity. The heavy-duty design resists mechanical abuse. This coupling has a female end fitting with union at one end and a female end fitting with a removable male nipple at the other end.