They certainly used to be in plastic binders with as far as I recall 17 sleeves (therefore 34 pages available). The problem was that as drills became more complex or other things had to be included we ran out of space. Now we have the front and back page laminated and the rest on 200 gsm card (for the moment, hopefully to be on waterproof paper idc) with tabs down the right hand side (for eg ENG, FIRE, ELEC etc) and further tabs along the bottom for individual drills. The heavies (Puma etc) are A4 high by A5 wide and the mediums (S76, 365 etc) are just A5.