I noticed the black housing looks clean on the rack and doesn't catch light in distracting ways.
IDEC RELAY & SOCKET BASE, SY4S-05 & RY45-UL, 7 A, 300 V, 24 V DC, LOT OF 5
What stands out about the WD3556 is how clearly it's printed on the side of the relay.
The heavy duty feel comes from thicker metal and firm mounting tabs that do not flex under pressure.
What stands out about the unbranded brand is the lack of logos, keeping the look consistent with other anonymous hardware.