You are looking at a Warm Audio Warm Lifter (sadly no box).
In as new perfect working order.

What Warm Audio say:

• The Perfect Partner For Low-Output Mics In Studio & On StageThe Warm Lifter is an inline active microphone preamp designed to provide powerful gain to low output dynamic and ribbon mics and comes with premium features for live & studio use. Warm Lifter puts a balanced, 2.4k Ohm high-impedance mic pre with analog gain, tone filtering, and balanced JFET input at your fingertips at an incredible size and price.
• Built To Handle Anything AudioHaving 26dB on tap before hitting digital prevents a mixer or digital interface from being taxed beyond 40dB of onboard digital gain where the likelihood of artifacts and thinning of sound increases. Additionally, the Warm Lifter ensures you have extra headroom necessary to bring out the rich lower-midrange detail and presence that passive ribbons and many dynamic mics are known for, without adding digital gain artifacts or losing tone from aggressively long cable runs. Beyond gain, Warm Lifter also has a 100Hz high-pass filter and a 3kHz high-shelf boost to sculpt tones.