We can now fit the standard David Clark Speaker inserts into these leather and Cloth Flying helmets. We can also fit amplifiers to the Mic circuit bringing the output up to a level that will match modern 8.33 aircraft radios. Electret mics can also be fitted into the "H" Mask cavity effectively making the complete assembly the electrical equivalent of a David Clark H10.13.4. This eliminates all issues with compatibility.
Comm Cables can also be replaced with either the UK NATO / US 179 Helicopter or standard G. A. Twin plugs. We try not to disturb the original appearance as much as possible. These upgrades are well received by pilots of open cockpit aircraft. There are many advantages of upgrading as the electrical specification will then match modern 8.33 Radios.