The Inspiration Has Two Default set-points to take full advantage of this: 0.7 bar partial pressure of oxygen (ppO2) for use at the surface, and 1.3 bar for depth. Switching between them is a simple manual operation and the adjustment procedure is designed to prevent accidentally changing the ppO2. In menu mode these set-points can also be altered by the user to tailor your ppO2 to the type of diving planned.

All three of the oxygen sensor readings are displayed simultaneously on both master and slave display handsets alongside the chosen set-point, which allows you to monitor the health of the cells. The electronic controller automatically instructs the solenoid to inject oxygen that the diver has metabolised and maintains the chosen set-point .

Both high and low ppO2 levels activate an audible alarm – at a high of 1.6 bar and a low of 0.4 bar. Drills learned during the training course cover manually controlling the oxygen and diluent in the breathing loop.

Traditionally, one of the biggest problems encountered in diving with rebreathers is flooding the loop, causing a ‘caustic cocktail’ – water coming into contact with the chemical used to ‘scrub out’ the carbon dioxide produces a corrosive mixture if inhaled.

The Inspiration is very tolerant of small quantities of water entering, as there is a series of water traps and barriers in the loop, and the mouthpiece is easily opened and closed underwater – another skill covered on the course.

Any water entering the mouthpiece is forced into the right-hand counterlung by a trap at the top of the breathing hose. The diver hears a gurgling noise when this happens, and it’s perfectly okay to continue the dive with a small amount of water in the bottom of this lung. Most students on the course experienced this at least once. You must avoid diving head-down or doing somersaults, though, in case water finds its way back past the traps.

I found I used very little air on a dive – typically 25 to 30 bar from a 3-litre cylinder – because it is simply used for counterlung volume during descent, and lung volume adjustments during the dive. With CCRs gas consumption is measured by the quantity of oxygen you metabolise. Unlike open circuit, this remains the same at all depths. A 3-litre cylinder of oxygen filled to 200 bar costs £5 and should last six hours.

This leaves a large proportion of air available for bailing out to open circuit in the event of an emergency, another skill we covered in the entry-level course.

After a dive it is common to find a lot of condensation in the scrubber unit. It’s rectified by simply airing the unit after the day’s diving. Again, traditionally rebreathers have demanded a lot of maintenance, but during the Red Sea tests the Inspiration simply needed a change of sofnolime after about six hours’ diving. Factors such as a higher carbon dioxide production rate and colder water temperatures can shorten its life to half that. To refill the scrubber unit you need 2.4kg of sofnolime, which costs about £9.

The breathing hoses, mouthpiece and counterlungs need to be washed and disinfected at the end of a week’s diving trip – much in the way your scuba kit does. The two batteries that power the electronics last approximately 60 hours and cost around £11 each, and the three oxygen sensors – £200 for three – are reckoned to last between one and two years, depending upon frequency of use.

The Inspiration will only be sold to divers who have undertaken a special training course under IANTD or TDI guidelines. The course in Hurghada cost £300 and lasted four days. The prerequisite for the entry level course is Nitrox certification. BSAC is also preparing a course.

The Inspiration retails at £3,000 and for that you get two 3-litre cylinders – one for oxygen, one for diluent – with contents gauges for both, two counterlung breathing bags, breathing loop hose with built-in water traps, a carbon dioxide scrubber unit, a computerised oxygen controller system consisting of two micro-processor units with digital displays and separate power supplies, a harness and 16kg wings-style BCD with an Auto Air emergency demand valve. n

• Michael Hamilton’s course was arranged by The Diver’s Lodge in Hurghada and he stayed at the Intercontinental Hotel. For information on the Inspiration and training programmes, contact AP Valves on

01326 561040. Photographs of the Buddy Inspiration, courtesy of AP Valves.