3) Patriot 256gb micro SD card for extra file/photo/video storage - purchased on Amazon. Im surprise Nike put these out, the belt clasp slips and frays the canvas belt with the first wear, avoid! Even then it didnt workSending them back. The shelves are made from some cloth like material. Overall great product I bought these for my CNC machine but the t-bolts are too big to fit in the tracks of the table, The mat that comes with it is also great to protect the roof of the car. Our first pair of kid Chacos has been through three boys, now onto the fourth kid, still going strong. The hard surface I would suggest for day to day use and the soft for gaming due to mouse sensitivity settings. They are good quality, fit great, and they are soft and comfortable!