The 3DR Iris drone looks like a large, blue mechanical insect. Its curved body has four arms that extend out from its corners, each accommodating a brushless motor with a two-leaf propeller. It can be equipped with two types of landing skids according to the height of the payload you want to install under its belly.
This PDF manual has 8 pages and provides basic instructions for assembling and using this drone.
Does anyone know why 3D Robotics went out of business? They made excellent drones!