The JACK JK-A4C-C is a computerized single-needle lockstitch machine that uses an "Octopus" AI chip for high-speed, high-precision sewing. Key features include automatic thread trimming, foot lift, and back-tacking, a digital stitch length adjustment, and a direct-drive motor for quiet and energy-efficient operation. Its AI system optimizes feeding to reduce thread breakage, making it suitable for various materials.