This is the "resistor replacement box", a low cost solution, you can set flexible and fast resistor between 1R and 9999999R, 1R step precision. For educational experiments, electronic engineering design or test clipping are great applications. Design based on the resistor series theorem. 1/2 watt tolerance +/- 1% SMD resistors. High quality FR4 fiberglass PCB. Specification: Maximum operating voltage: 200V colour: green : PCB size: 90 x 35 x 10mm Package Contents: 1 x Resistor Board Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the a little different from the real thing. The measurement allowed error is +/- 1-3cm.