Highly regarded (blue version) Ashly SC-50 rack mount Limiter/Compressor. The condition is good to VG. Note that 2 faceplate screw are missing, but has no impact on stability of the unit when rack mounted. A classic 1970s analog peak limiter/compressor renowned for its smooth, transparent dynamics control and ability to add harmonic "dirt" or fatness. It is a single-rackspace, line-level mono unit heavily favored for electric guitars, bass, and vocals.