This case contains six 5lb units of Kansui Powder Type 4.
Type 1 is 100% Sodium Carbonate.
Type 2 is 60% Potassium Carbonate and 40% Sodium Carbonate. It is only available in the 6oz size.
Type 3 is 80% Potassium Carbonate, 15% Sodium Carbonate, and 5% Phosphate Salts. This is great for thinner, low-hydration noodles. The higher percentage of Potassium Carbonate gives you a harder noodle which is usually what you want for a thinner noodle like Hakata-style. The Phosphate Salts provide hydration assistance, making it easier for the flour to become hydrated and retain your kansui water.
Type 4 is 100% Potassium Carbonate. This is typically used in conjunction with Type 1 by those looking to customize their kansui composition.
Kansui is used to make fresh ramen noodles. Kansui Powder is mixed into water and then added to flour to make the noodle dough. Without kansui, it's not ramen.