An authentic mid-20th century mechanical teaching model made by BIO-FIZ, Poland, demonstrating the working principle of a two-stroke internal combustion engine. This educational model, constructed from cast aluminium and steel, shows the inner workings of a piston engine through a cutaway cross-section with clearly painted air/fuel intake (blue) and exhaust (red) passages. The movable crank and piston mechanism demonstrate compression and exhaust strokes when rotated manually. Mounted on a solid varnished wooden base, this model was used in technical schools and mechanical training institutes to teach the basics of thermodynamics and engine mechanics. Details: - Maker: BIO-FIZ - Type: Two-stroke piston engine cross-section model - Country of origin: Poland - Period: circa 1960s–1970s - Materials: Cast aluminium, steel, wood - Finish: Painted functional sections (red/blue), base varnished - Dimensions: approx. 30 × 15 × 10 cm - Condition: vintage condition; complete and functional, light patina from age Features: Working crank & piston, colour-coded channels, mounted base with manufacturer’s plaque A superb vintage educational instrument and an excellent display piece for collectors of mechanical teaching models, industrial design, or automotive history. All items featured in our auctions, including this historic BIO-FIZ engine model, are sourced directly from our private collection at OldMoneyWatches. We are dedicated collectors with a passion for rare and significant artifacts. Bid with complete confidence; you are purchasing from a trusted seller with top-rated reviews and a proven track record for authenticity, honesty, and meticulous shipping. We guarantee that the item will be shipped securely and promptly.