Little Story DIY Hydraulic Power Principle based 3-IN-1 Mechanical/Robotic Arm Toy by SAMBOX can freely change the working head: grasper, grab, suction cup. A variety of functions to meet your different needs. The toy does not need electricity and a motor, as water can drive the mechanical arm. The advanced exploration hydromechanical technology allows you to enjoy the joy of operating a robotic arm. Hydraulic robot arm kit is made of high-quality plastic material, safe and eco-friendly, firm, and sturdy, stable and wear resistant, durable, EN71 Certified. The STEM educational toy is designed to improve children's science, technology, engineering, and math skills, improve their imagination and creativity by building the robotic arm. Comes with instruction manual. Each step is explained in detail in the instruction manual, is easy for kids to understand to assemble. Best for your li ?l one as birthday gifts, Christmas gifts, party gifts, Children's Day gifts, and New Year gifts.