Sunnytech Hot Air Vertical Stirling Engine Motor Model Educational Toy Electricity SZ001 (Khaki) M051 Stirlingtechonline is exclusive distributor and the owner of the brand "SunnyTech"----Please be sure you receive an authentic SunnyTech stirling with SunnyTech logo and only sold by Stirlingtechonline to ensure 1-year 100% Satisfaction Guarantee. See play video : It's small size.You may receive and feel it's small, so please pay highly attention about the size before you click "BUY IT NOW" It is a amazing and fantastic product at this price,it can be a great gift to your families or friends. It also can be used for teaching purpose. Many of our customers comes from school,colleague,etc Suitable for 6 years and upwards. WARNING: CHOKING HAZARD - small parts. Not for Children under 3 years.