B-Line B121SS4 Eaton series strut fittings and accessories, 3.93" Height, 5.37" Length, 3.5" Width, 1.52lbs, Steel, Eight hole double corner connection, 90 deg, Thickness 1/4 in, Stainless steel type 304

The B121SS4 is an eight hole double corner connection fitting that joins strut at 90 degrees. The double corner form means it wraps the corner on two planes, so it ties two runs of channel together at a right angle using bolted holes rather than welding. Eight holes total give you four fastening points per leg.

Steel, supplied in stainless steel type 304. That makes it suitable for damp, washdown, food process and exterior runs where a plain electro-galvanized fitting would rust out. If your run is indoor and dry, a plated carbon steel corner connection covers the same geometry at lower cost.

Material thickness is 1/4 inch. That is the heavy end of strut fitting stock, which is why this one is used at load bearing corners in pipe and conduit racks rather than the lighter flat plate angles used for bracing only.

No. The B121SS4 ships as the fitting only, so you order channel nuts, bolts and washers separately. On a 304 stainless fitting, match the hardware to the fitting: stainless bolts and stainless channel nuts, otherwise the carbon steel fastener corrodes first and you lose the reason you bought stainless.

Order it as B-Line B121SS4. The SS4 suffix is the stainless steel type 304 version of the B121 eight hole double corner connection, which is the detail to get right if a spec calls for stainless on the job.

A plain 90 degree angle fitting bolts through a single plane and relies on a couple of fasteners to resist twist. The B121SS4 double corner connection engages the channel on two planes with eight holes, which resists rotation at the joint far better. Use the double corner where the corner carries load or where vibration is present; a single angle is enough for light bracing.