What is the flat fee on Gemini?

Excuse me, could you kindly elaborate on the flat fee policy implemented by Gemini? I'm particularly interested in understanding the specific amount or percentage that is charged as a flat fee, and whether it applies across all transactions or if there are any exceptions to this rule. Furthermore, does this flat fee vary depending on the type of cryptocurrency being traded, or is it a standard charge across the board? Additionally, are there any hidden costs or additional fees that one should be aware of when using Gemini's services? Your clarification on these points would be greatly appreciated.