Aqua kem blue concentrated toilet fluid is pleasantly perfumed and biodegradeable, it prevents odour build up and helps dissolve waste matter. 0.78 litre which makes a 2L solution.  See More Info.

Double Blue is concentrated to give you the same Elsan performance and reliability on which you've always relied. Now, however you only need use half the quantity giving you a big saving on each dose.
For all cassette systems and chemical toilets.
British standard 2893.2005