Nishimatsuya Front-Opening Short-Sleeve Undershirts - Set of 6 Purchased around April and used for about 2 months! The material can be used all year round. I chose all 100% cotton, and I selected patterns that can be used regardless of gender, so they can be used in the future, except for the strawberries and cherries ^ ^ Also, I have never washed them with adult clothes, and I have washed them with baby detergent. I preferred the front-opening type because it was easy, but I developed an allergy to the buttons and can no longer use them m(._.)m There are no noticeable stains or dirt, but please understand that these are used items that a baby has used. *May be compressed to reduce shipping costs.