Cla-2a Compressor Limiter -

: Its multi-stage release—where the first 50% happens quickly (around 10ms) and the rest can take several seconds—allows it to "glue" tracks together without sounding intrusive.

The original hardware was called a "Leveling Amplifier," not a limiter. Unlike an 1176, which catches peaks with a vice grip, the CLA-2A uses a combination of a T4 cell (an electro-luminescent panel) and a photoresistor to react to sound.