Most listings list Elmo-style onesies as 100% polyester, often described as microfiber for a soft, plush feel.
Most listings recommend machine washing and tumble drying; some specifically advise washing cold and tumble drying on low to help preserve colors and softness.
Listings generally describe Elmo union suits as a regular, straight-leg cut with cuffed sleeves and pant legs for a snug fit. Many toddler options are footless, while adult styles follow the same straight-leg, regular-fit profile.
Product details and descriptions commonly list the fabric weight as suitable for year-round wear; several listings explicitly market these pajamas as good to wear any season.
Toddler Elmo union suits commonly use a front, half-length zipper and sometimes include a zipper snap cover. Adult-style union suits in the results list full-front zippers or pullover designs.
The Elmo/dino-style onesies include 3D felt facial features, felt dinosaur spikes down the back, a detachable dino tail, and a zipper snap cover around the zipper area.
Common conveniences include a front zipper with a zipper snap cover (on some toddler styles), cuffed sleeves and pant legs to keep the fit in place, and detachable elements such as a dino tail or removable hood/cape on select designs.