AC Reverbs is a collection of 10 impulse responses you can use in any Convolution Reverb to add space, ambience, and depth to any sound source. These IR's have been made using vintage and modern hardware reverb units that can now be used in any Convolution Reverb plugin. Here's a list of the most common...
Space Designer (included in Logic, MainStage)
Convolution Reverb (Included in Ableton 9 Suite)
TL Space (included in Pro Tools)
IR-1 (Waves Plugin)
Altiverb (Audio Ease)
Reflector (Native Instruments, included in Komplete)
REVerence (Included in Cubase)
They work on this nice list of plugins and a lot more that are even free on the market. Please check your DAW feature list, chances are that if I didn't list it here you have a free one already.