Pin diameter and board thickness fit
The 1-5645986-2: This receptacle accepts a pin diameter range of 0.028" to 0.033" — the most common pin size for standard 0.025" square posts and round pins in that band. The socket depth spans 0.148" to 0.260", so it can accommodate both flush-seat and standoff pin lengths. The board thickness range is 0.031" to 0.125". The mounting hole diameter is 0.062".
Contact material and plating grade
The contact is beryllium copper, which holds its spring force through repeated insertions — a real advantage in field-service or test-fixture applications where the pin gets swapped multiple times.