Instant self-heating containers include a combinable reactant and activator used to generate an exothermic reaction for heating contents of the container. The device is constructed and arranged to sequentially direct the at least one beam of light to at least two spaced locations on the surface plane. The base plate has an upper surface on which a plurality of protrusions is formed, a curved bottom surface opposite to the upper surface, and a housing defined therein. A position pressed by the first pressing member on the sheet bundle and another position pressed by the second pressing member on the sheet bundle are shifted with respect to each other in the direction of the fold of the sheet bundle. 50% of expressed as FeO; from 0. The techniques utilize the directory to allow efficient access to the class file.