B-Line B24SH-120HDG Eaton series strut channel, 1.62" channel height, 120" channel length, 1.62" channel width, Steel, 14 Gauge, SH hole pattern, B24 channel type, Hot-dipped galvanized

SH is the slotted-hole back on the B24 channel. The back is punched along its length rather than left solid, so you can bolt the channel directly to structure, joists or wall anchors anywhere along the run without drilling in the field, and you can through-bolt two channels back to back. If you want an unpunched back for a cleaner look or full section strength, that is a different pattern and a different part number.

Hot-dipped galvanized is the finish on this one, which is the coating specified for exterior, wet and corrosive locations: rooftops, loading docks, parking structures, tunnels, wash-down areas. Pre-galvanized (electro-galvanized) strut is the indoor, dry-location finish and will rust at the cut ends and punchings outside. If the run is outside or gets hosed down, HDG is the right call. Field-cut ends still want a cold galvanizing touch-up.

The B24SH is Eaton B-Line's version of the standard 1-5/8 by 1-5/8 inch, 14 gauge slotted-back channel, and the section dimensions are the industry-common ones, so fittings sized for 1-5/8 inch strut work across brands. If you are matching an existing run in a building, measure the channel face and check the back punching pattern rather than going by brand name, since slot spacing and slot shape vary by manufacturer and by pattern code.

Cutting the 120 inch stick down is normal practice, with a chop saw and an abrasive or metal-cutting blade through 14 gauge steel. On this one the finish is the thing to watch: hot-dipped galvanizing is a coating, so every cut end is bare steel. Brush the ends with a cold galvanizing compound before you hang it if the run is outdoors or damp, or the corrosion starts at the cuts.