This is a set of 4 magnesium balls, each containing 100g of high-purity magnesium (99.95% or higher). They are double-stitched with thick thread. Washing for 15 minutes and rinsing once saves water. Soaking them in citric acid about once every three months will remove any film that accumulates from washing. Soak for a short time, as prolonged soaking can dissolve the magnesium. They are said to last for 300 washes, approximately one year, but if you wish, we can embroider the shipping date on them. The recommended amount is 100g for every 5kg of laundry. When magnesium mixes with water, it transforms into weakly alkaline water containing hydrogen. Weakly alkaline water has antibacterial, cleansing, and deodorizing effects. You can also use them in the bath for a hydrogen bath, and the remaining water can be added to soil to make it alkaline, promoting plant growth. Suitable for indoor drying and organic cotton. Do not use with silk, wool, cashmere, etc. Fabric softener is not necessary, but you can use it if you prefer. For acidic stains, please add detergent. Chlorine bleach cannot be used. Do not touch with bare hands. Do not use for drinking. They will be sent tied flat.