The sub-book is a high quality diving logbook, made of water-repellent rubber neoprene with all-round zipper. Size approx. 15,5 x 22,5 cm. It contains a very common 6-ring mechanism (19/19/51/19/19 mm) with a filling height of 20 mm.

The inner cover is made of durable black microfiber material and contains a zippered interior pocket over the entire height and 6 brevet card pockets and a small mesh pocket. The right side contains the smart-stamp loop and also an open full-height slip pocket and a mesh sleeve. A ballpoint pen tab is inserted on the sides.