Sealed vial subjected to an almost complete vacuum and having 4 blackened blades on one side and glossy on the other. Under the effect of a light radiation, each black side absorbs more light than the shiny sides of each blade and allows the gas located in close proximity to expand and push the blades.
Other SpecificationsBulb Ø: 80 mm.
Total height: 138 mm.
Mounted on a stable base.