Ratings that drive the fit
The 399100102: Contact and clamp plating both read tin-plated: copper-tin on the contact, nickel underplate on the brass clamp, tin on the bronze screw. The nickel underplate on the clamp is the detail worth noting — it keeps the cage structure rigid under repeated torque cycles where an unplated brass cage would cold-work over time. Cycle life for a screw clamp is not a contact-fretting problem the way it is for a snap-in housing; the limiting factor is how many times someone tightens the screw before the wire anneals or the thread strips. Operating range of -40°C to 130°C covers the thermal envelope of most cabinet and industrial floor installations without derating the current figure.