Use this fun, stackable model to explain the progression of cervical dilation and effacement. The ten removable rings depict each centimeter of dilation from 1 cm to 10 cm. The rings depicting 1 cm to 5 cm are blue to represent early labor, the rings depicting 6 cm to 8 cm are yellow to represent active labor, and the rings depicting 9 cm to 10 cm are pink to represent transition. Can also be used to discuss cervical effacement. Comes with protective carrying case. 5" x 2" x 5".