Рашгард Ocean & Earth BOYS FLAME THERMO SS

The Flame Thermo is a rash vest with a fleece lining added, and the difference matters. A plain rash vest handles sun and chafe but adds no warmth; the fleece here holds a thin layer of warm water against the skin.

The main use is under a wetsuit on days when a full winter suit is too much but a summer suit leaves a kid shivering after an hour. A thin thermo adds warmth without adding bulk: the wetsuit still fits, movement isn't restricted.

The second use is on its own in summer as a paddle shirt — rash-vest stretch, more warmth.

Who it isn't for. Winter. Cold water is beaten by neoprene thickness, not by a lining. For strong sun a long sleeve with UPF is better — the forearms are exposed here. And under a tight wetsuit it may simply not fit: count it as an extra millimetre.