Abstract: An extreme service measuring tape assembly especially adapted for deep sea diving use includes a rugged, easily cleaned and inspected assembly having a split case in which mating peripheral threads and an angled tape slot permit the two halves of the case to be screwed together, the angled tape slot being "L" shaped in one of the case halves with a portion matching a conventional tape slot in the other case half to accommodate the tape in slewed position permitting screwing the case halves together, followed by restored position for use of the tape in measuring; interlocking double spool structure aids guide and positive assembly; compass, magnet, securance, and special polygonal case shape are included in the preferred embodiment.