Posh SwimThe Posh One Piece Swimwear Comfort Fit Available in 6 Colors Bow, Sunhat, & Headband Available (sold separately) Size 6m 18m Swimwear runs true to size. for example, if you need a half size you should size up. Spandex is rarely used alone and is usually blended with other materials like cotton, nylon, or polyester to add stretch to clothing. Hand wash or delicate cycle. Hang or lay flat to dry.