Picking up where most jackets leave off the Patagonia Infant Boys' Nano Puff Jacket delivers predictable warmth when the mercury begins its long and chilly descent during the second half of the year. Much like the adult version the Nano Puff Jacket features a durable and bluesign approved polyester material that endures autumnal hikes and spit-up accidents alike. Meanwhile the DWR treatment fends off light precipitation and moisture (though the spit up--you're on your own) and the internal windflap that's located beneath the front zipper bolsters your tot's defense from cool winds. More importantly though the Nano Puff is equipped with the same eco-conscious insulation as the adult version providing warmth regardless of the weather. So you and your little ham are able to adventure and wander comfortably as the seasons change.