The Global Specialties PB-3 is a replacement breadboard socket for use with Models PB-503 and PB-503C Circuit Design Workstations. The PB-3 has a breadboarding area consisting of 2520 tie-points secured to a transparent plexiglass plate. The transparent plate allows for easy viewing of the breadboarding connections. The PB-3 is secured to the trainer with velcro.