Can someone explain what epi leather is to me?

Straight from Fashionphile's page:

"Louis Vuitton's epi leather line was created in 1986 as an homage to the grainy leather that they use in the 1920's for their travel pieces. It's a wonderful choice because of its hardiness- it's repels water beautifully and withstands daily wear with little effort. The leather itself is textured- and in two tones to give it that wonderful grained look. It has come in a variety of colors since its introduction. "