Geo Scientific Ltd. offers their oxyguard dissolved oxygen sensor, with a range from 0-50mV (with 5 mV per ppm approximately), 1k OHM output impedance, operates at 0-40C up to 10 atmospheres, has a 3meter cable and is 58mm in diameter and 59mm long, and comes in galvanic cell, self polarising, and self-temperature compensating types.