Here's the front of the unit.  
It uses a Dive Rite back plate with Ray DSV, hoses, and P-connectors.  The O2 add (red hose) and the diluent add (gray hoses) are visible.

Here's the left side of the rig.

The right side with the exhale counterlung, Argon quick mount bottle, KISS addition (just above O2 bottle, green quick disconnect into exhale above lung).

The back of the unit with a hose running from the tee on the exhale lung to the bottom of the center section.  The sensors are visible in the top of the center section along with the lime in the scrubber canister.

A top view with a hose running from the top of the center section to the tee on the inhale lung.  The O2 injection hose and connection is visible on the top of the exhale lung (left), with the diluent hose fitting hidden under the elbow on the inhale lung (right), KISS addition on exhale tee.

The bottom of the rig showing the counter lung drain plugs, first stages, hose off of diluent for dry suit inflation and Bailout regulator.

This is the one of the modified Sherwood BC inflator used for O2 & diluent add.  The LP hose from the first stage regulator connects at the upper left.  The gas then is injected into the top of the lung through the hose on the bottom left when the button is pushed.

On the left side I also have a quick disconnect setup for a 6cf Trimix bottle that is just like the Argon bottle on the right side but the valve would be up .... and it's not installed in the photo.

The right/front.

The modified Draeger P-connectors.

The Kiss addition system.

 

Here's how I made my KISS addition with an Airtrol  .003" orifice.  Just stick it in,  clamp it up, and plug it in.  The one in this picture is actually a .005" (white).

http://www.airtrolinc.com/

(The following pics are from the MOD3-Rev1 rig.)

This is the setup I use to dry out the scrubber and lungs after use.

And a close up of that setup.

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This is the portable rig I use on trips.

Read the text description here.