A retaining device for PCI card includes a chassis, a clipping plate configured for retaining a PCI card, and a latch member. The blotch may be in just one of several separations and multiple separations may be used, for example, to identify the blotch. Auxiliary lines coupled to the pipelines in the distribution assembly in each span include valves to regulate the supply of water and chemicals from the pipelines. The housing is provided with guide passages connecting the drainage holes to a space in which the balancer shaft is disposed for draining the oil. Thus the intermediate element may be wedge shaped to aid suppression of triple-transit signals.