From EHX:

The EHX Neo Holy Grail is an update to our wildly popular compact digital reverb, the Holy Grail. It contains three reverb algorithms: SPRING, HALL, and PLATE. All three algorithms were designed and tailored for the electric guitar, but they work equally well on most instruments and voices.

The SPRING algorithm is a re-creation of the classic spring reverbs that are found in many guitar amplifiers. The HALL algorithm simulates the reverberations heard in large spaces such as a concert hall or cathedral. The PLATE algorithm is an emulation of a metal plate reverb commonly found in high end recording studios during the 1960s and ‘70s. The PLATE reverb is a very smooth, tonally balanced sounding reverb that sounds great on many different instruments, especially vocals. True bypass switching ensures your tone won’t be affected when the pedal is bypassed.