Amphenol Quadrax contacts are specialized connectors designed for high-data-transfer-rate applications such as Gigabit Ethernet and serial FPDP. They offer advantages like low power consumption and excellent EMI compatibility. These contacts feature four strategically spaced inner contacts, forming two 100 or 150 Ohm matched impedance differential pairs, along with a rugged outer contact for enhanced durability. They are primarily used in MIL-DTL-38999 Series III connectors, requiring modification of the connector to accommodate the keyed contacts. Amphenol provides various sealing plugs and grommets for use with these connectors, catering to different application needs like PCB tails or metal sealing.