Board-to-Board Connectors are dedicated connectors that enable direct electrical connections and signal/power transmission between two printed circuit boards (PCBs) without cables. Their core advantages include high density, compact size and high reliability. They support various stacking heights and transmission rates, and can transmit high-speed digital signals, analog signals and high currents. Common types are classified by mating method into vertical mating, horizontal side mating and mezzanine types, and by pin pitch into mainstream specifications such as 0.3mm, 0.4mm, 0.5mm and 0.8mm. They are widely used in electronic devices with strict requirements for space and transmission performance, such as mobile phones, laptops, servers, automotive electronics and industrial control.