The API Audio 954 is a parametric EQ in the form of a piece of outboard gear that is not rackable in your traditional sense. They will fit within the API lunch box but aren't the standard rack size. The 954 is an all analog piece of gear and it is unique because it has the capabilities to be automated, although I've never ventured into this portion of the unit.
The configuration is very easy to understand and figure out as it is your basic EQ, with three bands in total - high, middle, and low. You can set your frequency for each with the bottom knob, and set the gain or cut with the top. I don't have a manual for the API Audio 954, but if you have any experience with EQs at all you shouldn't need it as the unit is easy enough to figure out how to use without it.
The sound quality of the API Audio 954 is extremely crisp and clear, and won't color your sound beyond what you set it to do. It is suitable for all types of instruments, and I typically use it for electric and acoustic guitars, bass guitar, keyboards of all kinds, and both lead and back up vocals. However, it is rare that I will track with this, as I like to go back and add EQ later during the mixing stage. The API Audio 954 EQ does its job effectively and does it with a top notch sound quality.
I've been using the API Audio 954 EQ for about three or four years and it has become one of my favorite pieces of outboard gear in terms of equalization. It has both the ease of use and top notch sound quality that you have come to expect from API gear. These are very rare and will cost a decent amount of money if you can find one, but if you have access to them at a studio, they are absolutely worth using. This being said, I wouldn't suggest picking these up if you are a home studio owner looking for a single EQ to track or mix with, as it is just too expensive. All in all, another stellar piece of gear from API Audio.