This effect is a mono to stereo plate reverb and uses a similar algorithm of CCRMA NRev. I have named this effect not NRev but NVerb in VST since the original NRev algorithm does not support stereo output. However, the name NRev is used in many places in the source code. There are 2 types of NVerb. One is a simple algorithm and the other one is a nested allpass algorithm. You can choose the type by changing the factor parameter. You will notice the factor parameter like 1-A or 4-B. The digit is the oversampling factor parameter and the A/B is the type of the reverb. Type A is the simple one and Type B is the nested one, which is more dense than Type A.