A back plate includes an inner part, a bottom part, an outer part, a folded part and a fastener. Recesses in formed in one or more dielectric layers and electronic components are positioned within the recesses. At least one of the holder constituting bodies moves in the vertical direction to change the positions of the holder constituting bodies relative to each other. The signal alerts an operator that elevators are positioned properly relative to a pipe body so that slips within the elevators will be properly engaged against the outer surface of the pipe and not a connection upset or large diameter external coupling.