Beautiful, hand-drawn illustrations in a two-color format Page references in the bottom corner for finding more information in Trail Guide to the Body. Call-out letters (a, b, c, d) next to each structure to help you identify the specific structure in question. Binder ring that lets you organize cards to study only those you need. Durable, coated cards (5 1/2″ x 4″) that are easy to handle and made to last.