Metallics IPB350 Bushings 3-1/2" Insulated (Jar 25)

Yes. The IPB350 is a 3-1/2 inch insulated bushing made for rigid conduit, and it screws directly onto the threaded conduit end. It gives you a smoothly rounded plastic surface at the end of the raceway so conductors aren't cut or abraded as they're pulled through.

Yes. The IPB350 is flagged both Buy American compliant and ARRA compliant, and country of origin is the United States. That covers the documentation most public agency, school district, and federally funded projects ask for on electrical fittings.

It's plastic, not metal. For the function it serves, protecting conductor insulation at the raceway opening, plastic is what you want: the molded rounded throat has no burrs or sharp edge to bite the wire. Keep in mind a plastic bushing is an insulator, so it does nothing for raceway bonding or grounding continuity, which still has to be handled by the fitting, locknuts, or a bonding bushing.

They solve the same problem at different points. The IPB350 screws onto the threaded end of the rigid conduit itself, so it's the answer where conduit terminates into an enclosure, pull box, or stub-up with no connector doing the job. If you're using a fitting that already has a molded insulating throat, you don't need a separate bushing on that termination. A bushing is also what you reach for on existing conduit where you can't replace the termination hardware.

A jar of 25 is listed at 10 x 8 x 4 inches and 3 lbs, which is small enough to carry on the truck with the rest of the rough-in material rather than treating it as a freight item.