You will find that this power relay suits both small boxes and larger panels with ease.
FUJITSU FRL251A0120/02CS DPDT POWER RELAY 120V AC COIL 10A 240V AC OR 30V DC USA
A nice touch is the compact shape, which leaves room for other parts in crowded enclosures.
I appreciate the 4 Pack because it saves time when a relay fails unexpectedly.