Kids Scientific Toys DIY Science Educational Kit Experiment Hydraulic Experiment Lift Table Projects Physics Teaching Aids Model: CN-L0002 Material: wood Suitable age: over 5 years old Product size: 11*11*6.5 cm (4.33*4.33*2.56 inches) Knowledge point: air pressure and hydraulic principle Note: the price is for 1 set. The product doesn't need batte