Abstract: The present invention is in respect of a rule or measuring rod, also referred to occasionally as a measuring stick, and in particular in respect of the type of rule which comprises a number of telescopic components so arranged as to slide in relation to each other. The components may be clamped together in pairs by means of a locking device, and each component is in the form of a rail of U-shaped or essentially U-shaped section. The extremities of the legs of the section are in the form of projections which face each other; the individual components themselves are of identical section, but are of different sizes so that the components are able to slide inside each other.