Industry standard dual mic pre-amp
The gain control is switched, and has 12 positions. The first position gives -6 dB gain, in other words it attenuates (reduces the volume of) the signal, and is for use with microphones that have very high output levels. Each subsequent position increases the gain by 6 dB, up to a maximum of 60 dB.
All in very good condition as pictured
here's a link to the product spec sheet >FOCUSRITE<