"I really LOVE this costume. My son is a medium or 7/8 in boys and I bought a size large. The arms and legs of the costume are long so I am just gonna hem them. He might of fit into a medium but i was afraid that it was gonna be snug around the crotch area. It is roomy enough that when he put it on with his t-shirt and shorts that he was still comfortable. It is so worth the 34.99! The material is the normal fabric that most costumes come in. The head and the gloves are good quality. You wont be disappointed."