The overall rack dimensions height (A), width (B) and depth (C) are important when considering the space required for mounting on your wall.
The pocket width (D) is the maximum width card that can fit into the pocket.
The exposure (E) of most racks is 3/4 to 1 inch. This is the distance between one pocket and the next pocket. Once the card height exceeds the pocket depth by the amount of the rack's exposure, a taller card will gain no further exposure. For example the words TEST TEXT appear on the bottom card but only the word TEST appears on the cards above it. Given a 6.75" card and a 4" pocket depth, 2.75" of the bottom card is exposed but only the top 1.75" of the other cards is exposed, due to the racks exposure of 1.75"..
When choosing the pocket depth (F), be sure the pertinent card information for retrieval will be exposed. Ideally, your card height should equal the pocket depth + rack exposure + 1/4". Card height MUST exceed pocket depth by at least 1/2" or you will have trouble removing the card once it's inserted.
Pocket thickness (G) should be consider when using a rack for a special purpose other than single items, as brochure storage, etc. Most time card racks have a pocket thickness of 1/4" or less while file folder racks have a pocket thickness up to a 1/2" or more. Furthermore, time card rack slots are fixed, while multi-purpose rack pockets float allowing thicker items in some of the pockets but not in all..