ArmorColorChanger is very simple plugin which allows you to change the color of your leather armor with the specified hexadecimal color code. You can use the following command to change the color :
/color {colorNumber} - Color the armor in hand with the specified color code (hexadecimal)
The command take in argument the hexadecimal color code, for example "DADADA" or "D6E88A". You can use a color picker to choose the color. For example http://www.colorpicker.com/ or https://color.adobe.com/fr/create/color-wheel/
Source : https://github.com/Madeorsk/ArmorColorChangerPlugin
