This is the weight including the weight of the bag (approximately 3g). Since "Sentaku Mag-chan" is expensive, I bought a large amount of magnesium and made my own. I am selling the leftovers that I had stored at home. I have three more bags, so please let me know if you need more than one. I bought it several years ago, so it has turned black, but it is said that it will return to silver color when washed with citric acid water. It does not contain any surfactants, fragrances, fluorescent whitening agents, or bleaching agents that are included in conventional detergents. Just put the Sentaku Mag-chan in the washing machine with your laundry. The magnesium reacts with water to create weakly alkaline water, which can be expected to have washing and deodorizing effects. You can try it cheaply by making it yourself. It is safe to use about 50g in combination with detergent, and about 200g if using only Sentaku Mag-chan.