The Muscles Knee Joint with Removable Muscles model has 12-parts. The Muscle Knee shows different removable muscles and muscle portions of the knee area. Color-coded and raised areas indicate the muscle origin and insertion points on the femur, tibia, and fibula. Now included with all 3B Scientific Anatomy models is the 3B Smart Anatomy app. This app allows users to register their 3B item to extend the warranty from 3 to 5 years plus free 1 year access to the 3B Smart Anatomy app which includes 23 Anatomy lectures, 117 interactive models and 39 quizzes.