XX-Small (18 mos+) Like a wearable hug that provides steady proprioceptive input (body awareness) with deep pressure and balanced weight. The effect is so gentle, calming and reassuring, kids even ask to wear it. This vest is comfy, easy to use and will help kids quickly calm and focus. This vest can also be used to satisfy the wiggles. Ideal for kids on the autism spectrum and those with hyperactivity or sensory processing disorder.