The Gueneau S-001 is a rather interesting item. Probably evaluated by the Swiss AF with the aim to provide pilots with a "Super-Leichthelm" (Super Light Helmet) by the end of the '80.
Until today we have no evidence about any flight tests performed with this device.
Unconfirmed sources claim that it was designed by Gueneau with the support of Intertechnique during the R&D process of the EROS MP90/91 oxygen mask and related helmet-fitted connector receivers.
It looks as if those helmets were planned for the American and possibly Swiss market. Possible unbalance problems (?) stopped their development.
The helmet is identified as a S-001. Nevertheless, available data are supporting the possibility of the existence of an S-002 model.