What stands out about this relay and socket is the clear instruction sheet, which speeds-time setup.
ALCOSWITCH MPS103F PC MOUNT OR SOLDER PUSHBUTTON SWITCH ON-(ON) SPDT 125V 3A
You will find that DEC relays give quiet operation and reliable contact action in typical control panels.
With WD3556, the part number is right there, and small detail really helps during maintenance.