The Development Process of Fetus (Half-Size) model, often used in medical education, typically features an 8-part set illustrating human gestation from the 1st month to the 7th month, including a twin pregnancy, in a space-saving, 50% scale design. It showcases the transition from embryo to fetus, with anatomical, detailed, and durable PVC representations of fetal positioning and growth. 

The 8-part model generally includes:

• 1st Month: Early-stage embryo, showing initial cell development.
• 2nd Month: Continued embryonic development and basic structural formation.
• 3rd Month: Recognizable human features begin to form, and it is now considered a fetus.
• 4th Month: Fetus positioned in the uterus, often showing the breech position.
• 5th Month (A): Fetus in transverse lie and breech position.
• 5th Month (B): Twin fetuses in a normal position.
• 7th Month: A larger fetus nearing full development, showing significant growth in length and weight.