Beryllium copper (C17200 & C17300) is an age-hardening alloy that attains the highest strength of any copper base alloy. It may be age hardened after forming into springs, intricate forms, or complex shapes. It is valued for its elasticity, corrosion resistance, stability, conductivity, and low creep.

Beryllium copper, also known as copper beryllium, beryllium bronze, and spring copper, is a copper alloy with 0.5–3% beryllium. Copper beryllium alloys are often used because of their high strength and good conductivity of both heat and electricity