It's formed from 12 gauge steel to ASTM A1011 with a 33,000 PSI minimum yield. That's the same base material spec B-Line uses across the strut fitting line, so it behaves predictably alongside the rest of the channel hardware on the run.

Electro-plated zinc is a light indoor-duty coating. It's fine for dry interior runs, mechanical rooms, and covered areas, but it isn't the finish to pick for exterior exposure, washdown, or corrosive environments. For those, go to a hot-dip galvanized or stainless trolley instead.

A trolley rides inside strut channel on bearings so a load can travel along the run instead of being fixed in place. Electricians use them for festoon cable systems, sliding light fixtures, moveable drops over benches and equipment, and cable management on machinery. The B477ZN is the light duty two bearing version, meant for loads up to 50 lbs; a fixed load doesn't need a trolley at all, a standard strut nut and fitting will do.

Order Eaton B-Line B477ZN. The ZN suffix is the electro-plated zinc finish, and it's the single configuration this trolley is built in, so there's no handing, size, or finish choice to specify on the order.

No agency certification applies to the B477ZN. It's a mechanical strut accessory, not an electrical device, so it carries a material spec (12 gauge ASTM A1011, 33,000 PSI min yield) and a 50 lb design load rather than a listing. If your spec calls for listed support hardware, that requirement usually lands on the channel system, not the trolley.