The Unitree R1 is an ultra-lightweight humanoid robot priced from $4,900, standing up to 123 cm tall and weighing approximately 27 to 29 kg. Available in AIR, standard, and EDU variants with 20, 26, and 26 to 40 degrees of freedom respectively. The AIR has 4-DOF arms with no waist or head DOF, while the standard and EDU add 5-DOF arms, 2-DOF waist, and 2-DOF head with binocular camera (monocular on AIR). The EDU optionally adds dexterous hands and an NVIDIA Jetson Orin module (40 to 100 TOPS). All variants feature 6-DOF legs with hollow internal cable routing, low-inertia high-speed internal rotor PMSM joint motors with crossed roller bearings, and local air cooling. The knee joint range is -10 to +139 degrees and hip joints ±157 degrees yaw, -168 to +146 degrees pitch. A 4-mic array, speaker, Wi-Fi 6, Bluetooth 5.2, quick-release smart battery, and manual controller are standard. Battery life is approximately 1 hour. It integrates a Large Multimodal Model for voice and images with fully open joint and sensor control interfaces and support for mainstream simulation platforms. The EDU variant supports secondary development. Continuous OTA upgrades are standard. Targets research applications.