ESP never produced this model as a production guitar. They made this guitar in a 4 and a 5 string but the 6 string was never made. This is the sample/prototype for the 6 string version. I think they made this guitar in 3 colors and made 2 of each color ( Red, Black and Brown) for a total of 6. 

This is a sample/preproduction guitar. ESP makes the samples to test out various colors, finishes and to show to dealers prior to the actual model being
built. They take them to shows like NAMM and start taking preorders for the new years model. Some Samples are never make it into production models.