Non-pill polar fleece that will not shrink, fade or go out of shape.  No zips or Velcro.  Simply pulls on over the head.  Wide V cuts for boys (just in case their aim is not the best).  The purple jungle pj's are a semi-plush nylon mix material and does not have any stretch.  Best to go up a size for the purple leopard only.  Machine washable and cool tumble dry.