|Top of absorbent canister looking into space where sensors and solenoid
fit when assembled. Inhaled gas comes in on right, down the central tube to the
bottom, then back through the absorbent, past the sensors, and out to the mouthpiece via
the opening on the left. Note top absorbent bulkhead in background and threaded top
end of central tie rod in foreground.
The shoulder in main cylinder is because acrylic tubing varies somewhat in size and we machined it out to a standard I.D. so the electronics bulkheads and end closures could be made to a standard size.