3-Piece Conduit Coupling, 3-1/2″, Iron for Impact-Resistant Fit
https://nsiindustries.com/product/3-piece-conduit-coupling-3-1-2-iron-for-impact-resistant-fit/
The Bridgeport 3-1/2″ 3-Piece Malleable Iron Conduit Coupling joins two threaded rigid or IMC conduits for an impact-resistant fit.