The SIR-6 is a 14 Position Forcible Guided PC Board Relay Socket. A 250VAC, 10amp Relay would mate to this socket (which is what you see in the white version in the photo).
The KT708 is an 8 position PC Board Relay socket. An example of an application would be for use with a crane lift control.
Relay socket for 11pin octal or undecal relays, 3PDT screw connections. DIN Rail mountable. Finger Safe. UR , CSA, and CE. 12 Amps 300 Volts (CSA) and 10 Amps 300 Volts (USA).
Relay socket for miniature power relay or miniature switching relay with or without solid state relay, 2PDT spring-cage connections. DIN Rail mountable. Finger Safe. UR , CSA, and CE. 10 Amps 300 Volts
Relay socket for industrial relays with 4PDT, spring-cage connections. Finger Safe UR , CSA, and CE. DIN Rail mountable. Finger Safe. UR , CSA, and CE. 10 Amps 300 Volts