The HIOKI FA1813 is a high-precision 4-arm dual-sided flying probe tester specially developed for high-density package substrates, IC bare boards and fine-line PCB inspection. Equipped with 2 upper arms and 2 lower arms, it supports simultaneous top & bottom probing without custom fixtures, perfectly matching R&D verification, small-batch trial production and high-end substrate quality inspection. It adopts high-resolution dual cameras with 2× optical zoom and laser thickness compensation, realizing ultra-fine pad probing down to 2 μm. The optimized probe stroke control greatly reduces probe indentation damage on micro pads, and built-in 4-terminal low-resistance measurement delivers stable measurement for embedded components and ultra-fine circuits. Matched with standard UA1801 Process Analyzer software, it uses AI statistical analysis to dig out latent defects hidden in qualified boards, improving substrate yield and reliability. Optional built-in heating module enables high-temperature resistance testing to simulate thermal stress conditions of packaged chips.