A portable media player is configured with a flip form factor in which a flip cover is hingedly fixed to a main body portion of the player. Each of the first and second guide plates has a plurality of protrusions extending from an outer side thereof and recesses defined in an inner side thereof. After that, an intermediate medium is introduced in the basic form between the optical element and the form bed and, subsequently the optical element being removed together with the intermediate medium from the basic form. This tile can be colored with heat resistant glazes, stains and oxides and sized or shaped within certain dimensional ranges, so as allow it to present patterns, designs or even pictures on the sides, floor and back of the firebox. The invention further relates to a paper or paperboard produced according to the process and a headbox used in the process. According to this lamp holder, the cover plate made of metal is provided at a place of the lamp holder where out gas would be most likely to be produced if a resin material were used at such place, preventing a portion of the resin cover member from being provided at such place.