A rotational molding oven for forming an object from a mold containing resin therein. A light receiver receives the light beam and produces a signal indicative of the amount of light received. The wing includes two U-shaped configurations that together define a substantially H-shaped configuration for retaining the spacer between adjacent spinous processes. Access is not impeded by the door trim. This layer makes it possible to improve the image distortions due to the drop in the high voltage during current spikes delivered by the high voltage. The RAID controller outputs the data blocks and parity data block to the error detectors, respectively.