The Divex AH5 is the successor to the Divex AH3 and AH4, the helmet that has long been accepted by many commercial divers as the standard for safety, quality, performance and reliability.

The AH5 incorporates two major design modifications:

1 The air inlet has been moved from the rear of the helmet to the manifold block on the front right position.

2 The noise level within the helmet has been reduced by re-routing the incoming air. The lightweight, free-flow helmet isdesigned to be used either fitted with its own neck-seal, or locked directly into a drysuit. Because it combines many of the advantages of both the traditional hard-hat helmet and of modern diving masks, the AH5 is recommended for tasks as diverse as heavy construction, mobile inspection, for protracted dives in cold and polluted waters, and nuclear diving. Locked into a drysuit, the AH5 can give the diver protection in polluted waters, and it also allows the diver to control his buoyancy by adjusting the helmets’s valves. One option for the AH5 is to increase the maximum over-pressure within the helmet. This option is frequently used with a locked-on drysuit. Weights are added to allow the diver to adjust his buoyancy and become substantially negative at his place of work-to reduce the effects of strong currents and the high reactive force from work tools.

The same increased over-pressure option plus extra weights is also used to improve drysuit/helmet system integrity for the diver in nuclear reactor ponds and other polluted waters. If the suit should leak then the increased over-pressure results in air escaping out of the suit and not water inwards.

Although the AH5 is light it is extremely strong. The monocoque headshell is made from hand-laid impact resistant glassfibre. The area around the main inlet is over 1¼” (32mm) thick. Compared with closefitting helmets and breathing systems comprising oral-nasal masks and faceseals, the AH5 has many advantages. It is more comfortable because it gives the diver complete freedom to move his head within the helmet, communications are clearer, and because there is no air-demand system, breathing resistance is near zero, even when the diver is working strenuously.