Well, it's usually on the sweet side, with a lumpy, irregular but basically cylindrical shape, about 1"x6", fairly firm and dense. I was introduced to it by watching my Szechuan-born, Taiwan-raised stepmother: she would slice it crosswise (at an angle, to maximize surface area) and brown it before adding it to some other dish (often rice gruel, but it goes well in fried rice too). "Kam Yen Jan" is a major brand fairly widely available in the US.