Modular switches are provided with different capabilities so that they can serve a wide variety of purposes. Some of them are designed to stay in a condition once that condition is selected, others are designed to stay in a given condition for a set amount of time and then to revert back to their original condition. Switches of any operation type can be mounted together on the same board, keeping the same uniform look, despite their many different functions and types.
Latching modular switches remain as they are left once you change their state. For instance, if you push the switch in to make the circuit, the switch will remain in that position until you push it again, breaking the connection. These switches are types of maintained switches, but have the latching feature. The latching feature is usually added to provide an additional element of safety. In some cases, the most critical switches will be secured with a key so that they cannot be changed by people without authorization. There are also switches that latch with a padlock, which are typically installed on machinery that needs to be locked out and tagged out when someone is in an area where turning the machine on presents a hazard.
Maintained switches keep their state when you turn them on or off. The most common examples of these types of switches are light switches. When you turn them on, they stay on. When you want to turn them off, you flip the switch in the other direction to cut the circuit.
A momentary switch keeps the contact for a given period of time and then goes back to its former state. These are usually employed on time-delayed devices, particularly for security features. For instance, a safe that opens up when you press the correct combination may momentarily release the handle that allows you to retract the bolts in the door, but may automatically reengage if you fail to open the door within the specified amount of time.