Hello ; The gray ring related to the "multi-layer" and here is the definition of its role : **Multi-Layer**: Similar to the RatlineLayer. For multi-layer hole(Plated hole) display. If the PAD setting layer property as mult-layer, it will connect with all copper layers. There is two different violet rings one is related to the top solder mask layer and the other related to the bottom solder mask layer. You can have the full definition of the available layers through the following link : [https://docs.easyeda.com/en/PCB/Layer-Manager/index.html](https://docs.easyeda.com/en/PCB/Layer-Manager/index.html)