A flash circuit board in a lens-fitted photo film unit includes a board part, and a battery contact part connected to the board part by solder. The apparatus includes mechanisms for sealing and controlling the cover, and for coupling the combustion vessel to the cover while minimizing the thermal contact between them. A patterned insulation layer is formed on a second electric device, wherein the patterned insulation layer has a thickness between 5 \u03bcm and 400 \u03bcm, and an opening is in the patterned insulation layer and exposes the second electric device. An opposite surface of the plates from the vertebral body contacting surfaces is formed with a recess which serves as a bearing surface for the core.