This family of boxes holds up to 3 spare batteries, one SEF8A flash unit, and up to 3 SD cards, all used with Samsung NX series cameras. There are small bumps in each slot to keep the batteries, flash, and cards from falling out and similar bumps on the top cover to keep it from coming off until you pull it off. I printed in ABS using 0.25 mm layers, 3 top/bottom/shells and 20% infill. No support material required.