Audio & Design Recording were innovators in studio & broadcast gear in the 1970s & 80s, creating classics like the Compex
The Super Dynamic is one of their later models. It’s a two-channel limiter which can operate as two separate channels or as a stereo unit. It also has a ducking (voice over) facility. There are separate controls for each channel plus a link switch for stereo
Like the early ADR limiters, this can be a super-fast limiter to pin things in place. But, with adjustable attack & release controls, it can be more subtle, or slow attack & fast release can be combined to add snap to drums
The back panel has sidechain inserts for each channel plus a voice-over input, all on jacks. Main inputs & outputs are balanced on XLRs. There is also a DC control port to control VCA gain reduction remotely – probably a legacy of a broadcast use