This is a educational construction kit assembled from various materials (plastic, metal, etc.).
Named for the Rev. Robert Stirling, a minister of the Church of Scotland, the Stirling engine of his invention is an efficient, non-polluting engine that works on the principles of air expansion and contraction (thus it is sometimes called an "air engine"). This kit contains everything you'll need to build your own working Stirling engine, including a base.
An English-language instruction manual is now online as a downloadable PDF, courtesy of manufacturer Gakken.