A designed according to the principle of ohm's law and through the resistor in parallel through a different switch, can produce 3 kinds of resistance of a USB electronic load resistance discharge, when all the switch opens, is 2.2 ohm/10W, 4.7 ohm/10W, 2 kinds of resistance in parallel at the same time, in 5V voltage almost can produce 3A discharge current. The actual current size, please according to ohm's law: I = U/R Resistor in parallel calculation formula: R=1/(1/R1+1/R2+...+1/Rn) K1=4.7Ohm/10W , K2=2.2Ohm/10W Color: green Material: PCB+ electronic components Package Contents: 2 x USB Resistor Electronic Load Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.