Splash About This is a set sale of a wetsuit & swim cap! I decided to sell it because my child outgrew it after using it a few times for baby swimming. The cap was purchased on Mercari, so it feels slightly less orange than the wetsuit, but I think you can use them together without any problems. Please refer to the photos. Sizes are: Wetsuit: XL size (12-24 months) Swim cap: M size (18 months and up) My son is 10 months old, 75 cm tall, and has a head circumference of about 46 cm, and he wore this. At this point, the wetsuit still had room, and the swim cap fit perfectly! For your reference.