Whats Inside Animals Flash Cards4 years & up. 16 double sided photo x ray cards engage students in science exploration from the inside out! Images are protected with a special scratch resistant coating. Examine the photos and then place them on a light table or in a window to reveal the skeletal system of the animals! An excellent way to introduce children to animals and anatomy. Flip the cards over to get a better look at the skeleton. Teacher guide included. Cards are 8. 5' x 11'.