Use type definitions and strict type definitions to link all the instances of a custom object to a master definition so you can make changes to all instances by editing just the master. Type definitions are useful when you use the same control in many VIs. You can save the control as a type definition and use that type definition in all your VIs. If you change that control, you can update values that are part of the type in the single type definition file instead of updating the control in every VI that uses it. Use strict type definitions to control cosmetic properties.
Also, a type definition forces the control data type to be the same everywhere you use it. Use a type definition when you want to use a control of the same data type in many places and when you want to change that data type automatically everywhere you use it.
Refer to the Custom Controls, Indicators, and Type Definitions Application Note for more information on creating type definitions.