Circuit Breaker: This is a relatively new feature introduced in HollaEx 2.1 where users can turn on this mode to prevent large price fluctuation. In certain markets you do not want to have an immediate price drop/rise (say 20%) very quickly. Turning this feature on would help preventing these price changes over short period of time. Circuit breaker has a smart logic and simply having that on would make sure to avoid large price fluctuations. In case you are dealing with a market with large price fluctuations, it is better to have this feature off, otherwise it would cause many halts in trading resulting in a bad experience.