Description: DIY 4-DOF & 4 Axis Rotating Mechanical Robot Arm for Learning Scientific Kits Easy to assemble & control: only four knobs for controling the action of any part of the mechanical arm; also can be controled by computer orders after connecting USB 4 servos designed for high performance Can be used to test the servo motor coding for robotic engineers Suitable for learning and controlling theory of automatic robotic arm; guest space and students learning kits Also learn serial ports controlling servo and potentiometer controlling servo Main Material: Acrylic+Electronic Components Specification: Size: Approx 17 x 15.5 x 16cm/6.69 x 6.10 x 6.30inch It's not a finished one, needed to be assembled by yourself Feature: 1.4 degree of freedom robot arm with more untrammeled and flexible experience. 2.Most parts are integratedly punch-formed at one time,which is very strong and easy to install. 3.All movement joints are using high quality bearings with good precision. 4.Full 4 axis moving to do extra extension and support 180° robot servo. Package Includes: 1 Set 4DOF Robot Arm KitS with Servos