Aikuruc Swaddle, size M (for 6kg-8.5kg babies). Set of 2. Purchased on Amazon for 2380 yen each. I've been using the S size of this swaddle, and it really helps my baby sleep through the night, so I used the M size as well. I'm selling these now because my baby has outgrown them. The double zipper makes diaper changes so easy, as you don't have to take the whole thing off. I never had any leaks, either for pee or poop, so you can be assured of its hygiene. I used these every night for about a month. The zipper area is slightly worn from washing, but otherwise, there are no issues. Regarding washing, I only used Attack detergent, which is safe for babies, and I never used fabric softener. This is a set of 2, so you can use them every day for easy washing and changing.