The 3520 patterned sewing machine internet version comes with smart connected electronic controls, supporting WiFi/ethernet connections. You can remotely transfer patterns, monitor production, and troubleshoot issues. With a high-speed motor for thread cutting and a stable dual-shaft structure, it runs faster and handles thick materials more steadily, making it great for e-commerce and bulk factories. The standard version only works with a local USB drive, has no remote features, and is a bit sl