Plastic Bushing, 6″, Plain Plastic Used with Locknut
https://dev.nsiindustries.com/product/plastic-bushing-6-plain-plastic-used-with-locknut/
The Bridgeport 6″ 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.