Y="2.55"/> - 2 pin Molex header 2.54 mm spacing Pin header 2.54 mm spacing Q1, Q2, Q3 | 3 | 2N3904 | Small Signal NPN Transistor, TO-92 R16, R17, R19, R20 **Potentiometer, 9 mm pots, you're on your own! The jacks, like the SPDT toggle.\* In that case the pots and switches board ("Board B") must sit.