A rule assembly is described providing novel and beneficial features to the user. In a first aspect of the invention, an improved device and method is described for removably attaching the rule assembly housing to the clothing or equipment of a user. A beam is provided with a first and a second end, each end being connected to the housing to define a space sufficient to permit the introduction of a retention element for suspending the rule assembly. Preferably, the beam may pivot at the first end, and may be detachably lockable to the housing at the second end. In another aspect of the invention, means for making a preliminary determination as to the cause of any malfunction within the housing of the rule assembly is described. The housing of the rule assembly is provided with a window sealed with transparent material. A reel within the housing that carries a tape blade and a retraction spring is provided with at least one opening. The user may view the blade and/or the retraction spring from the exterior of the housing, through the transparent material and through the reel opening to assess its condition in the event of a malfunction.