Blue, red, brown, and black are all common switch types in mechanical keyboards, each with its own characteristics and suitable use cases. The specific differences are as follows:

Blue switch 

Blue switch is a type of mechanical keyboard switch with audible sound, moderate key force, and suitable for typing and gaming. Its biggest feature is the distinct "click" sound, with a trigger force of 50g and a clear tactile feedback, making it suitable for typing and gaming operations. When typing or gaming with blue switches, a distinct "click" sound can often be heard, so it is also known as "blue switch".

Red switch
Red switch is a type of mechanical keyboard switch with no audible sound, relatively light key force, and suitable for typing and gaming. Its biggest feature is the lack of distinct sound, with a trigger force of 45g, lighter than blue switch, and a trigger distance of 2mm, making it suitable for quick input operations in gaming.

Brown switch
Brown switch is a type of mechanical keyboard switch with a slight audible sound, moderate key force, and suitable for typing and gaming. The trigger force of brown switch is the same as red switch, both are 45g, but the trigger distance of brown switch is 2.2mm, slightly deeper than red switch, making it more suitable for typing. At the same time, brown switch also has a certain "click" sound, softer than red switch.

Black switch
Black switch is a type of mechanical keyboard switch with no audible sound, relatively high key force, and suitable for gaming and scenarios that require prolonged input, such as coding and typing. Its biggest feature is the lack of distinct sound, with a trigger force of 60g, heavier than red and brown switches, making it suitable for long-term input scenarios, such as coding and typing. The trigger distance of black switch is 2mm, the same as red switch.

Overall, blue switches on mechanical keyboards are suitable for typing and gaming users who enjoy hearing the distinct "click" sound; red switches are suitable for gaming scenarios that require fast input; brown switches are a compromise between the two and are suitable for typing and gaming; black switches are suitable for scenarios that require prolonged input, such as coding and typing.