Storm Tactical Pocket Data Books have a sturdy Polydura Cover and the same heavy duty plastic coils as the full size Data Books. * The book uses plastic coils, which have shown to hold up better than metal coils in the field. * Storm Tactical Pocket Data Books will fit in a pocket, large stock pack, backpack outer pocket, etc. * Storm Tactical Pocket Data Books were developed with, and tested by, Military and Law Enforcement Snipers. * Measures 5 x 3.7" with Storm TacticalTM Reticle Logo on cover.