Samtec SO Series Precision PCB Board Stacking Standoffs SO series PCB board stacking standoffs designed for use with Samtec SI connectors. These SO series PCB standoffs have a precision machined ruggedized design and are made from aluminium with a standard nylon locking compound. The thread of these SO series PCB board to board standoffs is 4-40 mm and the stand offs are available as female thread/press in (part numbers SO-xxxx-01-01-01) or a male/male configuration (part numbers SO-xxxx-02-01-01-L). These PCB standoffs are designed to be 0.15 mm longer than the connector stack heights to allow for processing variables, for instance, a standoff with a body height of 5.15 mm will have a stack height of 5 mm.