What is not allowed in BattleBots?

Can you tell me what exactly is prohibited in the BattleBots competition? Are there any specific types of weapons, materials, or designs that are not allowed? Are there any restrictions on the size, weight, or power of the robots? Additionally, are there any rules or regulations related to safety measures that participants must adhere to in order to participate in the competition? I'm curious about the specific guidelines and restrictions that are in place to ensure a fair and SAFE competition.