In Ragnarok X: Next Generation you can also upgrade your equipment to further develop your characters. It gives you additional stats aside from the base stats the equipment gives. Unlike the refinement simulator, there is no downgrade or break chance when upgrading your equipment.
In high level equipment upgrading, the chances of succeeding to the next level decreases. This is why REV.GG also built an upgrade simulator that can help players prepare for the materials they need to upgrade as it provides them the data with the average success rates and costs.