Description: Material: Crafted from metal material, this pulley system is designed to withstand regular use in educational settings, ensuring long-last performance Feature: This pulley block is compact yet effective, making it easy to handle and store while providing ample functionality for classroom demonstrations Easy Assembly: Designed with user convenience in mind, the components are easy to assemble and disassemble, allowing for quick setup and storage after demonstrations or experiments Educational Tool: Suitable for teaching fundamental mechanics concepts, this pulleys block physics experiment aids students in understanding the principles of force and motion through hands-on learning Versatile: This package includes a fixed pulley block, making it ideal for various physics experiments in middle school laboratories Specification: Material: Metal   Size Chart: Type A: 12.5cm/4.92inch Type B: 10cm/3.94inch Type C: 13.5cm/5.31inch Type D: 23cm/9.06inch Package Includes: 1 Piece Pulleys Block Physics Experiment Note: 1.This is not infant toy , please take away from children to avoid eating. 2.Please allow slightly errors 1-2cm/0.39-0.79inch differences due to manual measurement.