... *20 mm 3.colour: blue Blue Toilet Bowl Cleaner Block, Blue Eco Toilet Block, Toilet Blue Block Product Feature:Durability: it can ... the dirty both of the tank, rim, inner wall, sewer pipe and other parts of the toilet thoroughly; Acute Sterilization Ability: ... deodorization, and keep perfume continuously, purify the air of the toilet; Safety: neutral product, without any causticity or toxicity; ...