Steel sheet having a composition of ingredients containing substantially, by mass %, C: 0. The soft magnetic film is represented by a composition formula of xMyOz. Movement of the cutting blade assembly from a retracted position to an engaged position causes the cutting edge to engage a line, such as a monofilament trimmer line, to cut the line to a desired length. Each shelf is folded to extend into the interior space, where it is supported by ledges on the second side panel and held in place by tabs which snap into slots.