Package Include 1 x Variable Resistance Box Characteristics -Size: About 14.00X10.00X5.00cm/5.50X3.93X1.97in Experiment. -Material: Plastic variable resistor. -Color: Black Experiment Tool. - Very easy and convenient to use, it is very useful and durable experiment variable resistance box Physical Resistor Substitution Box. - Plastic material, flexibility and excellent durability, easy to use, for 300 ohm resistor. - Simple in structure, easy to use, simple appearance design, you can use it with confidence resistor box. - and durable. The simple resistance box is used as an additional resistance to expand the range of the voltmeter Variable Box 0-9999 Ohm. - It is used to measure the unknown resistance. It is used to measure the force and internal resistance of the power supply Substitution for Standard Resistors. Goods Description switch decade boxes Our variable resistance box is lightweight and reliable, portable and practical, suitable for school use.camping gas extension hose Simple in structure, easy to use, simple appearance design, you can use it with confidence