Description: 【Educational】Simple resistance box for students to conduct electrical experiments: verify part of the circuit Ohm law; use to measure unknown resistance; use known resistance to connect to the circuit to adjust the required current; use to measure the electromotive force and internal resistance of the power supply. 【Material】Lab Resistor Substitution Box is made of PP material, the resistance value does not change with the temperature, making the resistance measurement result more accurate. 【Knob switch】Knob switch designed to make measurement more easier. 【Physical】Variable Decade Resistor is Used for physical electricity experiment teaching. 【Adjustable 】Teaching Instrument Ohmmeters has Adjustable resistance range 0-9999Ω. Specification: Adjustable resistance range: 0-9999Ω Reference power: 0.5W Material: PP Size Chart: 16.5cmx12.5cmx6.5cm/6.50inchx4.92inchx2.56inch Package Includes: 1 Resistance Box Note: 1.This is not infant toy, please take away from children to avoid eating. 2.Please allow slightly errors due to manual measurement and different monitors.