Two brands in use, both about £1 to £1.50, one's DP brand and just called Soap Flakes, the other 's Granny's Soap Flakes (forget manufacturer) both about 450gr. First one has warning about using in washing machine, never caused any problems but I prefer sprinkling inside drum anyway as nothing gets properly "washed through" in my machine, even gels. Both brands are just "100% soap flakes", but have sometimes made up own mixture using ordinary grated soap.