With backlight power control, can be connected via jumper settings are backlight power. Plug the jumper to connect the backlight off, unplug the jumper to disconnect the backlight power.Contrast can be adjusted by turning the blue potentiometer clockwise increase, counterclockwise weakened. Potentiometer design on the front, enabling customers to freely adjust anytimeModules can be cascaded to cascade up to eight. By short-circuiting A0/A1/A2 modify the device address. The default address is 0x27.1602 LCD Display Size: 41.5 x 19 x 15.3mm (LxWxH)Supply Voltage: 2.5-6VSupports the I2C protocolThe product appearance and printed words depending on the batch, but this does not affect useColour:As ShownMaterial:PCBPackage Contents:10 x LCD2004 adapter boardsOnly 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.