inch thick which was formed to the desired configuration then heated and quenched employing acceptable spring tempering techniques at the upper extremity of the rear mounting bracket was constructed a deflection arm bracket 38 to which the deflection arm 37 was secured projecting forward from the front mounting bracket 32 and the rear mounting bracket 36 was an elongated guide arm 39 of 1 4 inch metal rod which projects forward and terminates in a ruler slide 41 in which was slidably positioned ruler 40 the metal ruler extends between the deflection arm 37 and the ruler slide 41 serving as a measuring reference with the ruler 40 being secured to the deflection arm 37 by ruler attaching means 42 the side of the ruler 40 facing the central body portion 10 in which is mounted a tv camera is normally graduated in reference marks 43 to permit observation of relative movement of the ruler 40 as transmitted by movement of deflection arm 37 the first species of the invention is the singular selfcontained unit including tv camera means and illumination means to observe the relative movement of the ruler 40 as the device progresses through a conduit or pipeline for the construction of the second species of the device reference is particularly made to fig3 and 5 the skid mounting structure and the central body portion 10 including upper skid frame 13 as well as bottom skids 25 and 26 are identical the variations in the second species of the device as illustrated in fig3 resides principally in the deflection arm means 37 39 and ruler 40 39 means in the second.