MIL-SPEX - 3 ½” x 5”
The "Rite in the Rain" Memo Books are bound with a Field-Flex cover. Small and flexible, they are perfect for keeping in your SHIRT pocket. The No. 954 has 112 pages (56 sheets). 
Waterproof
Useful reference material on the inside covers.
Fits in the chest pocket of Cadpat shirt
Smaller than FMP - 4 ½” x 6 ¾”