The mark consists of the three-dimensional configuration of roller guides. The roller guide includes three main components: the base, three pivot arms and the distinctive spring and bolt assemblies. All three pivot arms consist of two parallel surfaces of generally elongated oval shapes. The two "side" pivot arms are distinctive by the tabs that protrude from their sides. The two side pivot arms extend outwardly in a substantially V-shaped configuration from lugs cast into the base casting. The third "face" pivot arm forms an acute angle with the base and extends upwardly from a third lug on the base and bisects the V-shaped configuration formed by the other two pivot arms. Two of the spring and bolt assemblies extend in opposite directions from each other and extend substantially parallel to the base. They are attached to a large ridge-like portion of the base. The third spring and bolt assembly forms an acute angle with the base and a 90-degree angle with the face pivot arm. The base includes a substantially planar platform that has three lugs for attaching the pivot arms, as well as a large central ridge. The wheels depicted by dotted lines do not form any part of the mark in this application.