The Echo Series from Huayan Robotics is a line of seven-axis humanoid robotic arms with a coplanar cross-axis configuration. Models include the Echo 3, Echo 5, and Echo 15, with payloads from 3 kg to 15 kg. They feature full-joint force control with accuracy up to 0.02 Nm and 100 Hz control bandwidth, a large hollow internal routing diameter of 15 mm, and a lightweight design. A single controller can operate up to four arms, with native ROS2 support and edge AI decision-making for real-time trajectory adjustment.