I buy this sleep sack as I be look for something cotton and breathable as a alternative to fleece -lrb- = sweaty baby -rrb- . the product itself be very nice , soft and truly breathable but heavy at the same time . unfortunately the zipper be a flimsy plastic little nothing that should not be place on a baby product . after about 2 week of usage it open up -lrb- the zipper blocker on top come undo -rrb- and I find my kid 's lower body completely out of the sack as he be a wiggly sleeper and get himself out of it . it really scare I . anyway , I write to Aden + Anais describe the situation and be tell to send a photo and product series number . I receive a new blanket in the mail a couple day later ; however , despite the customer service representative 's explanation that the weak zipper be not a standard , the new blanket have exactly the same tiny plastic zipper . I do use this sack from time to time as my son be 9 month old now and I be less concerned with sid but I still do not understand how a product that be suppose to be upscale can be so unsafe . I compare the zipper on Aden + Anais with a cheap Halo and the Halo sack have a much sturdier zipper . another thing about this sack that be not so great be the fact that the fabric be very delicate and will rip and pill easily so I recommend wash it separately . anything with velcro -lrb- like a lonely bib bury in a pale of laundry -rrb- will absolutely ruin it . I would normally give this product 3 star . the fourth one be for the fact that I be give a new sack after e-mail the company .