Contacts can be made of any of several alloys, depending on the type of contact, the frequency of insertion and removal, and the electrical and environmental conditions in which the connector operates. Some commonly used materials and their applications are as follows:

Brass—Although brass is a material with good electrical conductivity, it is prone to deformation and rapid fatigue after repeated bending. It is usually used as a fixed contact in an inexpensive connector, or as other metal parts in the connector. Connectors with brass contacts should not be used where good resiliency is required. Of course, due to the low cost, brass can still be used competently as a contact in many places.

Phosphor Bronze - Phosphor bronze is harder than brass while maintaining longer-term elasticity. It is often used as a contact material for operating temperatures below 300°F. For most connectors with infrequent mating, or normal flexing of the contacts, the use of phosphor bronze ensures good reliability.

Beryllium Bronze - Beryllium bronze has far more mechanical properties than brass or phosphor bronze. Beryllium bronze parts set and harden after annealing, virtually retaining their shape permanently, and it is also the most resistant material to mechanical fatigue. In applications where frequent insertion and removal and high reliability are required, beryllium bronze is recommended.