What this unit is
The Mitsubishi FX3U-128MR/ES-A is a main unit from the FX3U series, offering 64 digital inputs rated for 100-240 VAC and 64 relay outputs, all powered from a 100-240 VAC supply.
Key ratings and what they mean for fit
64 inputs rated for line voltage AC (100-240 VAC); 64 relay outputs for general-purpose switching.