Each class set contains ten, 10-cm lengths of MW-127 LT wires with a brass ring terminal on each end. This is the type wire used in most projects in the Project Book. Two AA batteries activate the wire. Because students often have difficulty in securing the wire to end termination crimps, we provide these pre-made Muscle Wires. This is an economical way to involve students in experimenting with Muscle Wires. After showing students a few examples, ask them to create their own Muscle Wire Machine. While supplies last.