Onesie shirts are most often made from cotton and cotton blends, plus some stretch synthetics. Common materials listed include 100% cotton or cotton rib, cotton/polyester blends (for example 60% cotton/40% polyester), and nylon/spandex blends (for example 90% nylon/10% spandex).
Short sleeves are the most common sleeve length for infant onesie shirts, though the broader bodysuit category also includes long-sleeve styles. Product listings typically identify sleeve type as short sleeve or long sleeve and use simple, basic sleeve construction.
Onesie shirts are sold as single items and in multi-packs. Common listing formats include single-piece packages, 3-piece sets, and 4-packs of short-sleeve bodysuits.
Most listings target infants, with sizes labeled as Newborn and age-based sizes such as 3 months, 6 months, and 9 months. Items are generally marketed under "Infant" sizing.
Common features that aid dressing and diaper changes are envelope (lap-shoulder) necklines and crotch snap closures. Snap configurations often include three-snap or bottom-snap designs for quick access.
Care instructions most often recommend machine washing. Many listings also specify tumble drying; a minority note alternatives such as line drying or laying flat to dry.
