These remarkable springs, based on an alloy of nickel and titanium (Nitinol or NiTi), ‘remember’ to open up when heated and close again when cool.
If immersed in hot water at or around 90°C they will open in a split second and close as quickly if dropped in cold water. Such springs have many industrial applications – e.g., in sprinkler and fire damping systems where they replace expensive single-use only fusible links.
15mm x 11.5mm with a 9mm internal diameter.
The spring extends to approximately twice its length when heated.