The gold-plated PCB board provides enhanced conductivity, corrosion resistance, and durability. Their contacts or connectors along the edge of the PCB board serve as interface points for connecting and mating with other devices or components. The gold plating ensures reliable electrical connections, prevents oxidation and corrosion, and enables repeated insertions and removals without degradation in performance.

High-density applications: The use of a 4-layer PCB allows for increased component density and more complex circuit designs compared to lower layer count boards. This makes it suitable for applications that require higher functionality within a compact form factor, such as mobile devices, computer peripherals, and consumer electronics.

Signal integrity and EMI control: The presence of internal power and ground planes in a 4-layer PCB helps to improve signal integrity and reduce electromagnetic interference (EMI). The power and ground planes provide low impedance paths, shielding sensitive signals from noise, and enhancing the overall performance and reliability of the circuit.

Design flexibility: The multiple layers in a 4-layer PCB provide flexibility in routing signals and separating different types of signals, such as analog and digital, or high-speed and low-speed signals. This enables better signal isolation, reduces crosstalk, and allows for more efficient placement of components.

Gold plating advantages: The gold plating on the finger contacts offers several advantages, including excellent conductivity, low contact resistance, and resistance to oxidation and tarnishing. These properties are beneficial for applications that require reliable and long-lasting electrical connections, such as memory modules, expansion cards, or high-frequency connectors.