Appleton L400 Conduit Locknut Brand: Appleton. Part Number: L400. Appleton NEER Conduit Locknut, Standard, Series: L Series, 1-1/4 in NPSL, For Use With: Threaded Conduit/Connectors, Steel, Electro-Zinc Plated, 2.07 in W x 0.29 in H. Additional Description: APLE-L400 1-1/4 IN STL LKNT. Catalog Description: Conduit Locknuts, 1.25 IN Trade Size, 2.08 IN Diameter, 0.15 IN Height..