These products are produced with a usage of copper and Silver alloy like silver Nickel (AgNi) with various Ni content. Nickel is a refractory material which is very malleable. Adding Ni to Ag improves  the hardness of the silver and allowing it to retain good mechanical properties after undergoing an electrical arc. The high conductivity of the material and its easy handing makes it ideal for intense applications provided that current is low apparatuses, eg: relays, contactors, circuit breakers.