4-Hole T Gusset Plate - Electro-Galvanized allow for connections at the joints of your strut channel frame that sit flush to the top of two channel lips meeting at a T. Gussets have greater surface area than traditional corner flat fittings. The corner plates use 9/16" punched holes. Electro-Galvanized Steel should be used in interior applications where conditions are dry, and humidity is low.