The above image shows a portion of the original harness, the huge scrubber and the twin 2-liter oxygen cylinders, rated at 200 BAR (2900 psi). The counterlung has been removed. The rig is relatively large, and the attached upper carrying-handle (the sturdy V-shaped rod here on the left) is a nice touch for handling the rig. Also, the on/off valve for the on-board O2 tanks is located at the lower RH corner of the shell (the green knob at the upper RH side of the rig seen in the above image). This valve is easily accessed by the diver during the dive.
It looks complex, but it's really just an assembly of individual components having various functions. The tubing is of high quality, with all of the fittings being silver-soldered in place. No compression fittings are used in any of the components. Also, note that the bottom of the chassis is protected by a relatively thick heavy-duty flange, which supports the weight of the rig during suit-up. A very convenient addition to the IDA-72. The gauge shown in the lower center is for viewing the internal cylinder pressure, viewable through an opening in the outer shell and it was used primarily for pre-dive checks.
* IDA-72 is the abbreviation for the Russian words, Isolirujuschiy Dykhatelnyi Apparat ("Insulating Breathing Apparatus") and the year of development (1972). This information furnished by my friend Tina Molodtsova, at the Russian P.P. Shirshov Institute of Oceanology, which incidentally, is the oldest and the largest Russian research center in the field of oceanology.