Plastic Bushing, 3-1/2″, Plain Plastic Used with Locknut
https://nsiindustries.com/product/plastic-bushing-3-1-2-plain-plastic-used-with-locknut/
The Bridgeport 3-1/2″ Plastic Bushing terminates and protects conductors inside threaded rigid and IMC conduits when entering a box using a simple locknut. The bushing is temperature rated to 105°C.