Double Pole Double Throw Relay.
Note the wire forming the coil
and the linkage from the armature to the common contact.
Double Pole Double Throw Relay.
Mains operated relay.
Note the heavy duty contacts.
'Post Office' type relay.
Note the multiple contacts.
Multicontact Post Office type relay.
Note some contacts are NO and others are NC.
'Burnt contacts on a mains electricity relay.
The sparks produced when the relay switched
have seriously damaged the contacts.