Swiss net summer helmet
The origins of the Swiss Netzkopfhaube unfortunately are still unknown to us. If they were either officially imported from Germany (with the arrival of the Bf 109G in 1944 ?) , partially "donated" by interned Luftwaffe pilots or manufactured in Switzerland (by whom ?) remains a mystery.
One of several assumptions is that the Swiss took a specimen of a Luftwaffe LKpN101 from an interned pilot and then produced their own version. Photographic evidence indicates the existence of several variations of the helmet. While the adjustable top hook for 3-strap oxygen masks resembles the German original, simple square wire loops below the ear covers provide lateral attachment points for the Huggenberger mask.
The specimen on the official photograph to the left (shown in combination with a T-30 throat microphone) features the classic hook used for American and British oxygen masks. One might safely assume that snap fasteners are present on the opposite side.