IO Stura Facile Sodium Hydroxide Drain Cleaner, 1 l

Carefully unscrew the cap. In the case of cleaning a partially clogged drain, pour 1 or 2 doses of the product directly into the drain, even in the presence of standing water, wait about 2 hours, and then flush with warm water (not boiling).
When cleaning a completely clogged drain, pour about half a bottle and wait 3 – 4 hours, then flush with warm water. If necessary, repeat the application, possibly adding one or two extra doses. Between applications, wait at least 30 minutes and remember to flush the drain with water after each application. Do not stay around the drain while waiting: the reaction may generate heat. After using the product, carefully close the container.

Do not use a plunger. Do not mix with acids, bleaches, or other cleaning agents. Wear appropriate protective clothing and protect exposed skin before use.

Avoid contact with acids and metals, especially aluminum, tin, lead, and gold surfaces. For enamel surfaces, whirlpools, or colored surfaces, check the durability of the colored or enamel surface in an inconspicuous area beforehand. When cleaning small drains, use half the recommended dose.