The DB-905 PORTABLE ANALOG / DIGITAL TRAINER is an ideal teaching aid for all types of electronic circuits, Located all around the 2230 Tie-Point removable breadboard is a variety of functional input and output circuits, which can be used to stimulate or measure electrical signals from the circuit under test or development. The removable breadboard area is not connected to these peripheral circuits and is meant to be connected by the user using standard solid AWG #22-30 wire. These circuit functions allow for the breadboarding and testing of circuits without the need for many expensive individual pieces of equipment.